NUREG/CR-5738

Field Investigations for 

Foundations of 

Nuclear Power Facilities 

U.S. Army Corps of Engineers 

U.S. Nuclear Regulatory Commission 

Office of Nuclear Regulatory Research 

Washington, DC 20555-0001
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NUREG/CR-5738

Field Investigations for 

Foundations of 

Nuclear Power Facilities 

Manuscript Completed: September 1999 

Date Published: November 1999 

Prepared by 

N. Torres, J. P. Koester, J. L. Llopis 

U.S. Army Corps of Engineers 

3909 Halls Ferry Road 

Vicksburg, MS 39180-6199 

E. G. Zurflueh, NRC Project Manager 

Prepared for 

Division of Engineering Technology 

Office of Nuclear Regulatory Research 

U.S. Nuclear Regulatory Commission 

Washington, DC 20555-0001 

NRC Job Code W6453
Field Investigations for Foundations of Nuclear Power Facilities

ABSTRACT 

This document provides a technical basis for revision of the U.S. Nuclear Regulatory Commission 

Regulatory Guide 1.132, Site Investigations for Foundations of Nuclear Power Facilities, reflecting 

current and state-of-the-art techniques related to field site investigations. The report summarizes the 

processes of acquiring geological, geophysical, geotechnical, and other kinds of relevant information that 

may affect the construction or performance of a building or other engineered structure at selected sites. 

Guidance is presented for in situ site studies during the various stages of site characterization. Topics 

range from initial information gathering, literature review, and site reconnaissance investigations, to 

on-site testing and the collection and management of samples for laboratory testing. Specific laboratory 

tests and techniques for the engineering analyses of soils and specific requirements for liquefaction 

analysis are not addressed in this document but are covered in companion technical basis documents.

°°. NUREG/CR-5738
Field Investigations for Foundations of Nuclear Power Facilities 

TABLE OF CONTENTS 

A B ST R A C T ........................................................................ 111 

PR E FA C E ......................................................................... ix 

O V ER V IEW ....................................................................... xi 

1 GEOLOGIC SITE ASSESSM ENT .................................................... 1 

1.1 Development of a Conceptual M odel .............................................. 1 

1.2 O ffice Study .................................................................. 2 

1.2.1 Existing Literature ....................................................... 2 

1.2.2 M ap Studies ........................................................... 12 

1.2.2.1 Topographic M aps ............................................... 12 

1.2.2.2 Geologic M aps .................................................. 13 

1.2.2.3 M ineral Resource M aps ........................................... 13 

1.2.2.4 Hydrologic and Hydrogeologic Maps ................................ 13 

1.2.2.5 Seism ic M aps ................................................... 14 

1.3 W alk-over Study ............................................................. 14 

1.3.1 Geologic Field Reconnaissance ............................................ 14 

1.3.2 Geologic Field M apping .................................................. 15 

1.3.2.1 Areal M apping .................................................. 15 

1.3.2.2 Building Construction Sites ........................................ 17 

1.3.2.3 Borrow and Quarry Sites .......................................... 17 

1.3.3 Construction M apping ................................................... 17 

1.3.4 Remote Sensing M ethods ................................................. 18 

2 GROUNDWATER INVESTIGATIONS .............................................. 19 

2.1 G eneral ..................................................................... 19 

2.2 M ethods of Observation ........................................................ 22 

2.2.1 W ells ................................................................. 22 

2.2.2 B orings ............................................................... 22 

2.2.3 Piezometers and Observation W ells ......................................... 22 

2.2.4 Springs and Surface W ater ................................................ 24 

2.2.5 Tracer Testing .......................................................... 24 

2.2.6 Geophysical M ethods .................................................... 24 

2.3 Perm eability Testing .......................................................... 25 

2.3.1 Tests in Piezometers or W ells .............................................. 25 

2.3.2 Pum ping Tests .......................................................... 27 

2.3.2.1 Time-drawdown Test ............................................. 27 

2.3.2.2 Distance-drawdown Test .......................................... 28 

2.3.3 Perm eability of Rock .................................................... 28 

2.3.4 Pressure Tests .......................................................... 28 

3 BORINGS AND EXPLORATORY EXCAVATIONS .................................... 29 

3.1 B orings ..................................................................... 29 

3.1.1 Boring M ethods ...................................................... . 30 

3.1.1.1 AugerBorings .................................................. 31 

v NUREG/CR-5738
Field Investigations for Foundations of Nuclear Power Facilities

3.1.1.2 Drive Borings ................. 

3.1.1.3 W ash Borings ................. 

3.1.1.4 Rock Core Boring .............. 

3.1.2 Soil Identification and Description ........ 

3.1.3 Rock Core Logging .................... 

3.1.3.1 Lithologic Description .......... 

3.1.3.2 Rock Quality Designation ....... 

3.1.3.3 Solution and Void Conditions .... 

3.1.3.4 Rock Joint Description .......... 

3.1.3.5 Photographic and Video Record... 

3.2 Borehole Examination ....................... 

3.2.1 Visual Records ....................... 

3.2.1.1 Borehole Photography .......... 

3.2.1.2 Borehole Camera and Borescope .. 

3.2.1.3 Borehole Video Camera and Sonic I 

3.2.2 Alignment Surveys .................... 

3.3 Exploratory Excavations .....................

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3.3.1 Test Pits, Shafts, and Trenches .................... 

3.3.2 Calyx Hole M ethod .............................

4 SAMPLING METHODS ................................. 

4.1 Techniques for Recovery of Undisturbed Samples ......... 

4.1.1 Hand Trimming of Block Samples ................ 

4.1.2 Thin-wall Tube Samplers ....................... 

4.1.3 Fixed-piston-type Thin-wall Tube Samplers ........ 

4.1.4 Foil and Stockinette Samplers ................... 

4.1.5 Large-diameter Laval Sampler ................... 

4.2 In Situ Soil Testing ................................. 

4.3 Alternative Sampling Techniques ...................... 

4.3.1 Hand sampling ............................... 

4.3.2 Freezing Sampling ............................ 

4.3.3 Chemical Stabilization or Impregnation ............ 

4.4 In Situ Sampling for Specific Site Conditions ............. 

4.4.1. Cohesive and Plastic Soils ...................... 

4.4.2 Slightly Cohesive and Brittle Soils ................ 

4.4.3 Very Soft Soils ............................... 

4.4.4 Saturated Silt and Loose Sand ................... 

4.4.5 Compact or Stiff and Brittle Soils ................ 

4.4.6 Hard and Partially Cemented Soils ................ 

4.4.7 Gravelly Soils ................................ 

4.4.8 T ills ........................................ 

4.4.9 Materials Unsuitable for Construction ............. 

4.4.10 Collapsible Soils .............................

5 GEOPHYSICAL INVESTIGATIONS ......... 

5.1 Spectral Analysis of Surface Waves ....... 

5.2 Measurement of Strain-dependent Properties

6. IN SITU PHYSICAL TESTING ............... 

NUREG/CR-5738 vi

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Field Investigations for Foundations of Nuclear Power Facilities

6.1 In situ Tests - G eneral ......................................................... 62 

6.2 In Situ Soil Testing ........................................................... 64 

6.2.1 The Standard Penetration Test (SPT) ........................................ 64 

6.2.2 Becker Penetration Test (BPT) ............................................. 66 

6.2.3 D irect Shear Tests ....................................................... 66 

6.2.4 Field Vane Shear Tests ................................................... 66 

6.2.5 Plate Bearing Tests ...................................................... 67 

6.2.6 Pressurem eter Test ...................................................... 67 

6.2.6.1 Borehole Pressuremeter ........................................... 67 

6.2.6.2 Self-boring Pressuremeter ......................................... 68 

6.2.6.3 Displacement Pressuremeter ....................................... 68 

6.2.6.4 M archetti Dilatometer ............................................ 68 

6.2.6.5 Cone Penetrometer Test ............................................ 68 

6.3 In Situ Rock Testing .......................................................... 69 

6.3.1 R esidual Stress .......................................................... 71 

6.3.1.1 Overcoring M ethod .............................................. 71 

6.3.1.2 Photoelastic Inclusion M ethod ...................................... 71 

6.3.1.3 Flatjack M ethod ................................................. 71 

6.3.1.4 Hydrofracture M ethod ............................................ 71 

6.3.2 In situ Deform ability Tests ................................................ 72 

6.3.2.1 Cham ber Tests .................................................. 72 

6.3.2.2 Uniaxial Jacking Test ............................................. 72 

6.3.2.3 In Situ Uniaxial Compressive Test ................................... 75 

6.3.2.4 Other Deformation Tests .......................................... 75 

6.3.3 Determination of Dynamic Moduli by Seismic Methods ......................... 78 

7 HANDLING, FIELD STORAGE, AND TRANSPORTATION OF SAMPLES ................ 78 

7.1 Undisturbed Sam ples .......................................................... 78 

7.1.1 B lock Sam ples ......................................................... 79 

7.1.2 Sample Storage in Tubes ................................................. 79 

7.1.2.1 Cohesionless Soils ............................................... 79 

7.1.2.2 Cohesive Soils .................................................. 79 

7.1.3 Sam ple Rem oval ........................................................ 82 

7.1.3.1 Cohesionless Soils ............................................... 82 

7.1.3.2 Cohesive Soils .................................................. 82 

7.1.4 Sample Transportation ................................................... 82 

7.2 Disturbed Sam ples ............................................................ 82 

7.3 Care and Storage ............................................................. 83 

7.4 D isposal .................................................................... 83 

7.5 Low-Level Radioactive Waste and Mixed Waste .................................... 83 

REFEREN CES ..................................................................... 83 

APPENDIX A GEOLOGIC MAPPING PROCEDURES OPEN EXCAVATIONS ............. A-1 

APPENDIX B GEOLOGIC MAPPING OF TUNNELS AND SHAFTS ...................... B-1 

APPENDIX C EXAMPLES OF DRILLING LOGS ...................................... C-1 

vii NUREG/CR-5738
Field Investigations for Foundations of Nuclear Power Facilities

APPENDIX D METHODS OF SUBSURFACE EXPLORATION .......................... D-1 

APPENDIX E SPACING AND DEPTH OF SUBSURFACE EXPLORATIONS FOR SAFETY

RELATED FOUNDATIONS ........................................................ E-1 

LIST OF FIGURES 

Figure 1. Diagram for the development of regional geology ................................ 16 

Figure 2. Example of report quality log with lithologic, blow count, moisture, and well completion 

inform ation . .............................................................. 23 

Figure 3. Single packer and double packer techniques (RTH) ............................... 26 

Figure 4. Early thin-walled open-drive samplers, Hvorslev 1940. (Clayton, Matthews, and 

Sim ons, 1995) ............................................................ 39 

Figure 5. Hvorslev fixed-piston thin-walled tube sampler (Clayton, Matthews, and Simons, 

1995) . .................................................................. 40 

Figure 6. The Laval tube sampler (Clayton, Matthews, and Simons, 1995) ................... 42 

Figure 7. General operation of the Laval sampler (Clayton, Matthews, and Simons, 1995) ........ 43 

Figure 8. Standard Penetration Test equipment (Clayton, Matthews, and Simons, 1995) .......... 44 

Figure 9. Method of sand sampling by freezing probe (after Yoshimi, Hatanaka, and Oh-Oka, 1977) 47 

Figure 10. Uniaxial jacking test. (RTH) ................................................ 74 

Figure 11. Plate-loading equipment. (RTH) ............................................. 76 

Figure 12. Details of plate tests equipment. (RTH) ....................................... 77 

Figure 13. Block sampling (Clayton, Matthews, and Simons, 1995) ........................... 80 

Figure 14. Procedure for freezing of samples (Konrad, St. Laurent, Gilbert, and Leroueil, 1995) ... 81 

LIST OF TABLES 

Table 1 Sources of Geologic Information (EM 1110-1-1804, Department of the Army, 1984) ...... 3 

Table 2 Special Geologic Features and Conditions Considered in Office Studies and Field 

Observations (EM 1110-1-1804, Department of the Army, 1984) ...................... 7 

Table 3 Instrument for Measuring Groundwater Pressure (Dunnicliff, 1988) .................. 20 

Table 4 Applications of Selected Geophysical Methods for Determination of Engineering 

Param eters ................................................................ 55 

Table 5 Numerical Rating of Geophysical Methods to Provide Specific Engineering Parameters ... 60 

Table 6 In Situ Tests for Rock and Soil (adapted from EM 1110-1-1804, Department of the Army, 

1984) .................................................................... 63 

Table 7 In Situ Tests to Determine Shear Strength (adapted from EM 1110-1-1804, 

Department of the Army, 1984) ................................................ 65 

Table 8 In Situ Tests to Determine Stress Conditions (adapted from EM 1110-1-1804, 

Department of the Army, 1984) ............................................... 70 

Table 9 In Situ Tests to Determine Deformation Characteristics (adapted from EM 1110-1-1804, 

Department of the Army, 1984) ................................................ 73

NUREG/CR-5738 viii
Field Investigations for Foundations of Nuclear Power Facilities

PREFACE 

The study covered by this report was performed by the U.S. Army Engineer Waterways Experiment 

Station (WES) for the U.S. Nuclear Regulatory Commission (NRC) under Inter-Agency Agreement 

RES-95-006 during the period June 1995 to January 1999. The study was directed by Mr. Robert 

Kornasiewicz. Office of Nuclear Regulatory Research, NRC. 

The report was prepared by Ms. Nalini Torres, Dr. Joseph P. Koester, and Mr. Jos6 L. Llopis of the 

Earthquake Engineering and Geosciences Division (EEGD), Geotechnical Laboratory, WES. General 

supervision was provided by Dr. Mary E. Hynes, Chief, Earthquake Engineering and Geophysics Branch, 

and Dr. Lillian D. Wakeley, Acting Chief, EEGD. 

At the time of publication of this report, Director of WES was Dr. Robert W. Whalin. Commander was 

COL Robin R. Cababa, EN.

ix NUREG/CR-5738
Field Investigations for Foundations of Nuclear Power Facilities

OVERVIEW 

This document provides a technical basis for revision of the U.S. Nuclear Regulatory Commission 

Regulatory Guide 1.132, "Site investigations for Foundations of Nuclear Power Facilities," reflecting 

current and state of the art techniques related to field site investigations. The report summarizes the 

processes of acquiring geological, geophysical, geotechnical, and other kinds of relevant information that 

may affect the construction or performance of a building or other engineered structure at selected sites. 

This includes the detection and assessment of potential foundation problems, geologic hazards and 

ground water conditions that may affect planned constructions. This document provides a description of 

commonly used methods for subsurface exploration and characterization, and of the types of subsurface 

materials for which they are generally applicable. However, foundation conditions at a specific site are 

unique, and thus the geologists/geotechnical engineers must develop an exploration program and methods 

that suit the conditions at their site. 

This report is divided into sections covering procedures and requirements for a systematic field site 

characterization. Topics range from initial information gathering, literature review, and site 

reconnaissance investigations, to on-site testing and collection and management of samples for laboratory 

testing. The document is modeled from the Geotechnical Guide for Site Characterization produced by 

the U.S. Army Engineer Waterways Experiment Station (Engineer Manual (EM) 1110-1-1804) to assist 

those responsible for engineering projects of the Corps of Engineers. Specific laboratory tests and 

techniques for the engineering analyses of soils and specific requirements for liquefaction analysis are 

not addressed in this document but are covered in companion technical basis documents. 

This report organizes the various activities that may be required for a site characterization in a logical 

sequence that will support a complete study. Section contents are summarized in the following 

paragraphs. 

The Geologic Site Assessment section describes an office study, a walk-over study, and the development 

of a conceptual model and geotechnical data base as the first steps toward a site selection investigation. 

The office study consists of an intensive literature review to assure that all the previously available 

information of the study sites will be obtained and reviewed. This segment includes a section on general 

map studies. Recommendations are given for this process, as well as sources of published and 

unpublished information. The walk-over study is basically the "reality check" of all the remote and 

documentary information collected previously in the office study. The walk-over includes the review of 

the office data and on-site reconnaissance. A conceptual model and geotechnical data base are described; 

these should be developed from information acquired during the office and walk-over studies. The 

process of creating the conceptual model and data base starts with the information gathered in the office 

study, continues with the corroboration and collection of necessary information in the walk-over study, 

and culminates with the analysis of all the verified and customized information. The appropriate 

sampling requirements for a site characterization study are discussed, including such details as sample 

depth, layout, and spacing. Subsurface investigation methods for typical geologic conditions are 

included, as well as characterization needs and detailed explorations for unusual site conditions. The 

model and geotechnical database are continually updated as more information is acquired and 

performance data become available. 

The Groundwater Investigations section covers the requirements of a site characterization program 

related to assessment of subsurface water conditions. Groundwater studies include: observations and 

measurements of flows from springs and of water levels in existing wells, boreholes, observation or 

monitoring wells, and piezometers. This information is used with site geologic information to determine

xi NUREG/CR-5738
Field Investigations for Foundations of Nuclear Power Facilities

piezometric surface elevations and profiles, fluctuations in piezometric surface elevations, the possible 

existence and location of perched water tables, depths to water-bearing horizons, direction and rate of 

seepage flow, and potential for leakage from a proposed reservoir or beneath an embankment or levee. 

Descriptions of the information that can be provided by different types of piezometers and their specific 

installation requirements as well as other instruments and techniques and their advantages and 

disadvantages, are included in this section. Guidance and references are also included for instrument 

calibration, maintenance, and verification necessary to assure proper performance of the equipment and 

that reliable results are obtained. 

The Boring and Exploratory Excavations section describes the many drilling techniques and 

equipment available for site investigation. Rotary and percussion drilling, power augering, hand driven 

techniques, and other options are described. 

Sampling Methods Techniques for both disturbed and undisturbed sampling are discussed. Alternative 

sampling techniques are described and referenced for undisturbed sampling of hard-to-sample materials. 

Site-specific in situ sampling recommendations are presented according to soil type (e.g., cohesive, non

cohesive, fine-grained, coarse grained). 

The Geophysical Investigations section introduces and tabulates various engineering geophysics 

techniques applied to interrogate large areas and amounts of the subsurface for determination of 

engineering properties and the spatial distribution of geologic materials at potential foundation sites. 

Advantages and disadvantages of each technique are presented. 

The In Situ Physical Testing section includes discussions of the methods used in current practice for in 

situ testing of subsurface soils and rock. This section also describes in situ tests for specific site 

conditions, including penetration tests, in situ stress, compressibility tests, and deformation 

characteristics tests. 

The Handling. Field Storage, and Transporting of Samples section offers guidance and references for 

procedures for handling, transporting, and preserving disturbed and undisturbed samples.

NUREG/CR-5738 xii
1. Geologic Site Assessment

1 GEOLOGIC SITE ASSESSMENT 

1.1 Development of a Conceptual Model 

Nuclear power facilities require extraordinary assurance of public safety. Part of assuring this safety 

ensues from building nuclear facilities where geologic conditions are known and geologic hazards are 

minimal. Knowledge of the geologic setting that one gains through site investigation is a prerequisite to 

planning an engineering assessment of the site. That is, on-site and geotechnical engineering 

investigations can proceed in a cost-effective manner only after development of a conceptual model of 

the geologic setting. Most importantly, the exploration program and methods must be tailored to address 

the key foundation and geotechnical issues identified from the geologic conceptual model. 

A geologic conceptual model begins as the 3-dimensional mental picture or best guess of geologic 

conditions of the subsurface and how the site under consideration fits in its regional geologic setting. 

This mental picture is revealed by a study of all available geologic information, and refined through on

site reconnaissance and sampling. Details of the concept are changed with additional data, resulting in a 

sound basis for in situ measurements of materials properties and for creation of a sampling matrix for 

subsequent laboratory testing of engineering properties as needed for appropriate design and 

construction. The purpose of a geologic site assessment and subsequent activities of site investigation is 

to create this conceptual model and populate the model with useful geotechnical data. 

Several other types of information related to conditions in the shallow subsurface must be known about a 

site before it becomes a candidate for site investigation. The earthquake hazard potential of any site 

under consideration must be known. Regional information about earthquake hazards is available from 

published resources, and on-line as presented in later sections. Also, the likelihood of encountering 

cultural resources must by considered, to assure compliance with the Archeological Resources Protection 

Act of 1979 and the Native American Graves Protection and Repatriation Act of 1990. 

Aspects of the Clean Water Act (33 U.S.C. 1344) also must be considered. Construction activities that 

involve placement of fill into wetlands are regulated at the national level. State and local wetland 

protection laws also may apply. Identification and delineation of wetlands involves sampling of soils, 

vegetation, and hydrology according to guidance given in the 1987 Corps of Engineers Wetlands 

Delineation Manual. Information about applications for Section 404 permits for modifying wetlands can 

be obtained from District Offices of the Corps. Additional information about District Regulatory Offices 

is available at: 

http://www.usace.army.mil/inet/functions/cw/cecwo/reg/ 

Compiled and properly interpreted regional geologic data from the office study, coupled and 

corroborated with information obtained during the walk-over study, will provide the information 

necessary to identify suitable sites and to determine the scope of site investigations. A site model should 

involve the following: 

"* Tentative models should be developed for geologic conditions at the site. 

"* Establishment of micro-seismic monitoring network in the study area. 

"* Regional geologic conditions should be identified and incorporated into a regional geologic map. 

"* Preliminary assessment should be made of regional seismicity. 

"* Tentative sources of construction materials should be located.

1 NUREG/CR-5738
1. Geologic Site Assessment

1.2 Office Study 

The office study consists of an extensive literature review with the goal of obtaining and studying the 

significant and previously available information on the site. Information and data pertinent to the project 

can be obtained from a careful search through published and unpublished papers, reports, maps, records, 

and consultations with the USGS, state geologic and geotechnical agencies, other federal, state and local 

agencies, and private industry. This information must be evaluated to determine its validity for use 

throughout the project's development. Deficiencies and problems must be identified early so that studies 

for obtaining needed information can be planned to assure economy of time and money. Some of the 

basic aspects that should be covered in an office study include geologic conditions, meteorological or 

climatic conditions, existing constructions, previous land uses, previous mining activity, and 

geomorphological changes. Especially in the case of larger projects, data are most effectively compiled 

and analyzed in a Geographical Information System (GIS) format. Table 1 summarizes the sources of 

topographic, geologic, and special maps and geologic reports. Table 2 outlines the types of geologic 

features or conditions that should be identified from the various sources of information. 

1.2.1 Existing Literature 

Understanding the geologic and hydrologic conditions is the goal of an early site characterization 

program. The remainder of the site characterization program will involve the collection and analysis of 

site data to improve this understanding and determine engineering properties of the geologic materials. 

Information on topography, geology and geologic hazards, surface and groundwater hydrology, 

seismology, and soil and rock properties is reviewed to determine the adequacy of available data. 

Additional information such as groundwater, other subsurface information, and seismicity data will be 

needed at specific sites. These data are critical to long-term studies, requiring advanced planning and 

early action. 

General site topographic and geological characteristics should be obtained from existing topographic, 

geologic and geophysical maps. Available geologic and engineering geology maps, soil survey maps and 

records, geological publications, regional field trip guides, and journals should be reviewed for pertinent 

information. Geotechnical problems and conditions described in previous studies, journals, newspapers, 

and ground investigation reports should be identified. 

Climatic or meteorological conditions of the area can be obtained from existing meteorological records. 

Ground water conditions can be assessed from topographic maps, aerial photographs, well records, water 

supply and previous site investigation reports. 

Geomorphological changes through time can be observed as well as prior construction activities in the 

area. Knowledge of this information allows for a better understanding of the natural geologic-hydrologic 

system of the region and how it can be modified by the project. This information will allow better 

judgment for site selection and general project design and management. 

Most states regulate well installation and operation and maintain water well databases that extend back 

many years. Wells may be municipal, industrial, domestic, or may have been drilled for exploration 

and/or production of petroleum and natural gas. The information that is commonly available includes 

date of installation, screened interval, installer's name or company, depth, location, owner, and 

abandonment data. Lithologic and geophysical logs may also be available, and in some cases, production 

and water quality information. 

NUREG/CR-5738 2
Table 1 Sources of Geologic Information (EM 1110-1-1804, Department of the Army, 1984) 

Type of 

Agency Information Description Remarks

Topographic U.S. 7.5-minute series 1:24,000 (supersedes 1:31,680). 

maps Puerto Rico 7.5-minute series 1:20,000 (supersedes 1:30,000) Virgin

Island 1:24,000 series. 

U.S. 15-minute series 1:62,500 (1:63,360 for Alaska) 

U.S. 1:100,000-scale series (quadrangle, county, or regional format) 

U.S. 1:50,000-scale county map series 

U.S. 1:250,000-scale series 

Digital elevation models are available for entire U.S. at 1:250,000, 

one for certain areas at 1:100,000 and 1:24,000 scales. 

Digital line graphs are available for some areas at 1:24,000 and 

1:65,000 for: 

- Hydrograph 

- Transportation 

- U.S. Publication Survey 

- Boundaries 

- Hypsography 

1:24,000 (1:20,000 Puerto Rico), 1:62,500, 1:100,00, and 

1:250,000 quadrangle series includes surficial bedrock and standard 

(surface and bedrock) maps with major landslide areas shown on later 

editions 1:500,000 and 1:2,500,000 (conterminous U.S., 1974) 

Landslide susceptibility rating, swelling soils, engineering geology, 

water resources, and groundwater

Orthophotoquad monocolor maps also produced in 

7.5-minute and 15-minute series. New index of 

maps for each state started in 1976. Status of 

current mapping from USGS regional offices and in 

monthly USGS bulletin, "New publications of the 

U.S. Geological Survey"

USGS 

USGS 

USGS

Special maps 1:7,500,000 and 1:1,000,000: Limestone Resources, Solution Mining 

Subsidence, Quaternary Dating Applications, Lithologic Map of U.S., 

Quaternary Geologic Map of Chicago, Illinois, and Minneapolis, 

Minnesota areas

Hydrologic Investigations Atlases with a principal map scale of 

1:24,000; includes water availability, flood areas, surface drainage 

precipitation and climate, geology, availability of ground and surface 

water, water quality and use, and streamflow characteristics

Some maps show groundwater contours and 

location of wells

(Continued)

New index of geologic maps for each state started in 

1976. List of geologic maps and reports for each 

state published periodically 

Miscellaneous Investigation Series and 

Miscellaneous Field Studies Series, maps and 

reports, not well cataloged; many included as 

open file

Geology maps 

and reports 

Miscellaneous 

maps and 

reports

USGS

Hydrologic 

maps

USGS

z 

C 

O0

Q 0 

0 

0 

(JQ 

(i

(5 

(> 

(r• 

(5
Table 1 (Continued) 

Type of 

Agency Information Description Remarks

Earthquake 

hazard 

Mineral 

resources

z 

C) 

003

Bibliography "Bibliography of North American Geology" North American, Hawaiian 

Islands, and Guam 

Bibliography "Bibliography and Index of Geology Exclusive of North America" 

"Bibliography and Index of Geology"

Earthquake 

hazards

Remote sensing 

data 

Remote sensing 

data 

Remote sensing 

data

Operates National Strong-Motion Network and 

National Earthquake Information Service publishes 

monthly listing of epicenters (worldwide).

Published until 1972 

1934-1968 

1969 to present, 12 monthly issues plus yearly 

cumulative index

National Geophysical Data Center in Colorado contains extensive 

earthquake hazard information

Landsat, Skylab imagery See Table 4-2 of EP 70-1-1 for detailed information

The National Wetlands Inventory maps at 1:24,000 for most of the 

contiguous U.S. 

1:24,000 series maps outlining floodplain areas not included in Corps 

of Engineers reports or protected by levees 

"State-of-the-Art for Assessing Earthquake Hazards in the United 

States," Miscellaneous Paper S-73-1

Available as maps or mylar overlays 

Stage 2 of 1966 89th Congress House 

Document 465 

Series of 19 reports, 1973 to present

(Continued)

Seismic maps of each state (started in 1978 with Maine); field studies 

of fault zones; relocation of epicenters in eastern U.S.; hazards in the 

Mississippi Valley area; analyses of strong motion data; state-of-the

art workshops 

Bedrock and surface geologic mapping; engineering geologic 

investigations; map of power generating plants of U.S. (location of 

built, under construction, planned, and type); 7.5-minute quadrangle 

geologic maps and reports on surface effects of subsidence into 

underground mine openings of eastern Powder River Basin, Wyoming

USGS

USGS

0 

OQ 

o

Ct 

CD 

CD

USGS 

Geological 

Society 

of America

NOAA 

NASA 

NOAA 

EOSAT

USFWS 

USGS 

USAEWES

Wetlands 

Flood-prone 

area maps 

Earthquake 

hazard
Table 1 (Continued) 

Type of 

Agency Information Description Remarks

International 

Union of 

Geological 

Societies

NRCS 

FEMA

State Geologic 

Agencies

Un

National Imagery 

and Mapping Agency 

(NIMA) 

American 

Association of 

Petroleum 

Geologists 

TVA

Worldwide 

mapping 

Soil survey 

reports 

Earthquake 

hazard 

Geologic maps 

and reports 

Topographic 

Maps 

Geological 

highway map 

series 

Topographic 

maps, geologic 

maps and 

reports

Commission for the Geological Map of the World publishes periodic 

reports on worldwide mapping in "Geological Newsletter" 

1:15,840 or 1:20,000 maps of soil information on photomosaic back

ground for each country. Recent reports include engineering test data 

for soils mapped, depth to water and bedrock, soil profiles grain-size 

distribution, engineering interpretation and special features. Recent 

aerial photo coverage of many areas. Soils maps at 1:7,500,000, 

1:250,000, and 1:12,000 scale are available in digital format for some 

areas. 

NEHRP "Recommended provisions for Seismic Regulations for New 

Buildings and Older Structures," 1997, includes seismic maps. 

State and county geologic maps; mineral resource maps; special maps 

such as for swelling soils; bulletins and monographs; well logs; water 

resources, groundwater studies 

Standard scales of 1:12,500, 1:50,000, 1:250,000 and 1:1,000,000 

foreign and worldwide coverage including digital and photomaps 

Scale approximately 1 in. equal to 30 miles shows surface geology and 

includes generalized time and rock unit columns, physiographic map, 

tectonic map, geologic history summary, and sections 

Standard 7.5-minute TVA-USGS topographic maps, project pool maps, 

large-scale topographic maps of reservoirs, geologic maps and reports 

in connection with construction projects

(Continued)

L0 

004

Reports since 1957 contain engineering uses of 

soils mapped, parent materials, geologic origin, 

climate, physiographic setting, and profiles.

List of maps and reports published annually, 

unpublished information by direct coordination 

with state geologist 

Index of available maps from NIMA 

Published as 12 regional maps including Alaska 

and Hawaii 

Coordinate with TVA for available specific 

information

0 

0 

CD 

ob 

oj
Table 1 (Concluded) 

Type of 

Agency Information Description Remarks

Geologic maps Maps and reports prepared during project planning and design studies 

and reports

Agricultural 

Stabilization and 

Conservation 

Services 

Aerial Photography 

Field Office 

USGS Earth 

Resources 

Observation 

Systems (EROS) 

Data Center (EDC) 

SPOT

Aerial 

photograph 

Aerial 

photographic 

coverage 

Remote sensing 

imagery

The APFO offers aerial photographs across the U.S. typically a series of 

photographs taken at different times, as available for a given state 

The EDC houses the nation's largest collection of space and aircraft 

acquired imagery 

High resolution multispectral imagery produced by France's SPOT 

satellite imager is available for purchase

00 

,..4 

00

List of major current projects and project 

engineers can be obtained. Reports on 

completed projects by inter-library loan or from 

USAE Waterways Experiment Station for many 

dams 

Information is available at 801-975-3503 

Information is available at 605-594-6151 or 

800 USAMAPS 

Contact for SPOT images is at 800-275-7768

USBR

0 

0 

UQ 

(D~

(ON
Table 2 Special Geologic Features and Conditions Considered in Office Studies and Field Observations (EM 1110-1-1804, 

Department of the Army, 1984) 

Geologic Feature 

or Condition Influence on Project Office Studies Field Observations Questions to Answer

Landslides

Faults and 

--J faulting; past 

seismic activity 

Stress relief 

cracking and 

valley rebounding

Stability of natural and 

excavated slopes

Of decisive importance in 

seismic evaluations; age of 

most recent fault movement 

may determine seismic design 

earthquake magnitude, may be 

indicative of high state of stress 

which could result in foundation 

heave or overstress in 

underground works 

Valley walls may have cracking 

parallel to valley. Valley floors 

may have horizontal cracking. 

In some clay shales stress relief 

from valley erosion or glacial 

action may not be complete

Presence or age in project area or at 

construction sites should be 

determined 

Compute shear strength at failure. 

Do failure strengths decrease with 

age of slopes-- especially for clays 

and clay shales?

Determine existence of known faults 

and fault history from available 

information 

Examine existing boring logs for 

evidence of faulting from offset of 

strata 

Review pertinent geologic literature 

and reports for the valley area. 

Check existing piezometer data for 

abnormally low levels in valley sides 

and foundation; compare with 

normal groundwater levels outside 

valley

Z 

n 

C) 

O0

Estimate areal extent (length and 

width) and height of slope

Estimate ground slope before and after 

slide (may correspond to residual 

angle of friction) 

Check highway and railway cuts and 

deep excavations, quarries and steep 

slopes 

Verify presence at site, if possible, 

from surface evidence; check poten

tial fault traces located from aerial 

imagery 

Make field check of structures, cellars, 

chimneys, roads, fences, pipelines, 

known faults, caves, inclination of 

trees, offset in fence lines 

Examine wells and piezometers in val

leys to determine if levels are lower 

than normal groundwater regime (indi

cates valley rebound not complete)

(Continued)

Are landslides found off site 

in geologic formations of 

same type that will be 

affected by project 

construction? 

What are probable previous 

and present groundwater 

levels? 

Do trees slope in an unnatural 

direction? 

Are lineaments or possible 

fault traces apparent from 

regional aerial imagery?

0 

0 

CV 

C,, 

(a C( 

(a3
Table 2 (Continued) 

Geologic Feature 

or Condition Influence on Project Office Studies Field Observations Questions to Answer

Sinkholes; karst 

topography

Anhydrites or 

gypsum layers

Caves

Erosion resistance

Major effect on location of 

structures and feasibility of 

potential site (item 13)

Anhydrites in foundations 

beneath major structures may 

hydrate and cause expansion, 

upward thrust and buckling 

Gypsum may cause settlement, 

subsidence, collapse or piping. 

Solution during life of structure 

may be damaging 

Extent may affect project feasi

bility or cost. Can provide evi

dence regarding faulting that 

may relate to seismic design. 

Can result from unrecorded 

mining activity in the area 

Determines need for total or 

partial channel slope protection

Examine air photos for evidence of 

undrained depressions

Determine possible existence from 

available geologic information and 

delineate possible outcrop locations

Locate contacts of potentially 

erosive strata along drainage 

channels

Locate depressions in the field and 

measure size depth and slopes. Dif

ferences in elevation between center 

and edges may be almost negligible or 

many feet. From local residents, 

attempt to date appearance of 

sinkhole

Look for surface evidence of uplift; 

seek local information on existing 

structures 

Check area carefully for caves or other 

evidence of solution features 

Observe cave walls carefully for 

evidence of faults and of geologically 

recent faulting. Estimate age of any 

broken stalactites or stalagmites from 

column rings 

Note stability of channels and degree 

of erosion and stability of banks

z 

003

Are any stalactites or 

stalagmites broken from 

apparent ground displacement 

or shaking? 

Are channels stable or have 

they shifted frequently? Are 

banks stable or easily eroded? 

Is there extensive bank 

sliding?

(Continued)

Are potentially soluble rock 

formations present such as 

limestone, dolomite, or 

gypsum? 

Are undrained depressions 

present that cannot be 

explained by glaciation? 

Is surface topography rough 

and irregular without 

apparent cause? 

Are uplifts caused by possible 

hydrite expansion or "explosion"?

0• 

(5 

0 

Cr,
Table 2 (Continued) 

Geologic Feature 

or Condition Influence on Project Office Studies Field Oh-ervations Questions to Answer

Internal erosion

Area subsidence 

Collapsing soils

'1 Locally lowered 

groundwater 

Abnormally low 

pore water 

pressures (lower 

than anticipated 

from groundwater 

levels)

Affects stability of foundations 

and dam abutments. Gravelly 

sands or sands with deficiency 

of intermediate particle sizes 

may be unstable and develop 

piping when subject to seepage 

flow 

Area subsidence endangers long

term stability and performance 

of project 

Determines need for removal of 

shallow foundation materials 

that would collapse upon 

wetting 

May cause minor to large local 

and area settlements and result 

in flooding near rivers or open 

water and differential settlement 

of structures 

May indicate effective stresses 

are still increasing and may 

cause future slope instability in 

valley sites

Locate possible outcrop grea, of 

sorted alluvial materials or terrace 

deposits

Locate areas of high groundwater 

withdrawal, oil fields and subsurface 

solution mining of underground 

mining areas 

Determines how deposits were 

formed during geologic time and any 

collapse problems in area 

Determine if heavy pumping from 

wells has occurred in project area; 

contact city and state agencies and 

USGS 

Compare normal groundwater levels 

with piezometric levels if data is 

available

Examine seepage outcrop areas of 

slopes and riverbanks for piping

Check project area for new wells or 

new mining activity 

Examine surface deposits for voids 

along eroded channels, especially in 

steep valleys eroded in fine-grained 

sedimentary formations 

Obtain groundwater levels in wells 

from owners and information on 

withdrawal rates and any planned 

increases. Observe condition of 

structures. Contact local water plant 

operators

Are there any plans for new or 

increased recovery of 

subsurface water or mineral 

resources? 

Were materials deposited by 

mud flows?

Is a possible cause the past 

reduction in vertical stresses 

(e.g. deep glacial valley or 

canal excavations such as 

Panama Canal in clay shales 

where pore water pressures 

were reduced by stress relief)?

(Continued)

z 

C) 

00

0 

(5q 

Go 

(5
Table 2 (Continued) 

Geologic Feature 

or Condition Influence on Project Office Studies Field Observations Questions to Answer

2ý 

ý0 

t0 

0o

Varved clays

o

Dispersive clays 

Riverbank and 

other liquefaction 

areas

Provides early indication of 

stability of excavated slopes or 

abutment, and natural slopes 

around reservoir area 

Highly preconsolidated clays and 

clay shales may swell greatly in 

excavations or upon increase in 

moisture content 

Pervious layers may cause more 

rapid settlement than antici

pated. May appear to be 

unstable because of uncontrolled 

seepage flow through pervious 

layers between overconsolidated 

clay layers or may have weak 

clay layers. May be unstable in 

excavations unless well points 

are used to control groundwater 

A major factor in selecting soilS 

for embankment dams and 

levees 

Major effect on riverbank stability 

and on foundation stability in 

seismic areas

In situ shear 

strength from 

natural slopes 

Swelling soils and 

shales

Locate potential slide areas. Existing 

slope failures should be analyzed to 

determine minimum in situ shear 

strengths 

Determine potential problem and 

location of possible preconsolidated 

strata from available information 

Determine areas of possible varved 

clay deposits associated with 

prehis toric lakes. Determine 

settlement 

behavior of structures in the area 

Check with Soil Conservation 

Service and other agencies 

regarding behav ior of existing small 

dams 

Locate potential areas of loose 

fine-grained alluvial or terrace sand; 

most likely along riverbanks where 

loose sands are present and erosion 

is occurring

Are existing slopes 

consistently flat, indicating 

residual strengths have been 

developed? 

Do seasonal groundwater and 

rainfall or watering of shrubs 

or trees cause heave or 

settlement?

(Continued)

Estimate slope angles and heights, 

especially at river bends where 

undercutting erosion occurs. Deter

mine if flat slopes are associated with 

mature slide or slump topography or 

with erosion features 

Examine roadways founded on geo

logic formations similar to those at 

site. Check condition of buildings and 

effects of rainfall and watering 

Check natural slopes and cuts for 

varved clays; check settlement 

behavior of structures 

Look for peculiar erosional features 

such as vertical or horizontal cavities 

in slopes or unusual erosion in cut 

slopes. Perform "crumb" test 

Check riverbanks for scallop-shaped 

failure with narrow neck (may be 

visible during low water). If present, 

determine shape, depth, average 

slope and slope of adjacent sections. 

Liquefaction in wooded areas may 

leave trees inclined at erratic angles. 

Look for evidence of sand boils in 

seismic areas

0 

0 eq 

I-) 

(D 

CD 

C,)
Table 2 (Concluded) 

Geologic Feature 

or Condition Influence on Project Office Studies Field Observations Questions to Answer 

Obanlclhitr fst

Relatively recent filled areas 

would cause large settlements. 

Such fill areas may be 

overgrown and not detected 

from surface or even subsurface 

evidence

Check old topo maps if available for 

depressions or gullies not shown on 

more recent topo maps

Obtain local history of site 

from area residents

Local 

overconsolidation 

from previous site 

usage

Local areas of a site may have Obtain local history from 

been overconsolidated from past residents of area 

heavy loadings of lumber or 

material storage piles

Filled areas

z 

00 

00h

0 

0 

CJQ 0 

0 C/) 

Cn
1. Geologic Site Assessment 

All existing and previous construction activities should be investigated. Services such as water and gas, 

electric, and telephone lines in the area should be documented from construction (as-built) drawings, 

topographical maps, plans held by utilities, and mining records. The locations of power lines, pipelines, 

access routes, and ground conditions that could restrict the location of or access to borings should be 

noted. Local construction practices and the condition of existing structures and roads should be observed 

and potential problems also noted. State DOT's may have detailed record of highway and bridge boring 

programs in the area. 

Previous land uses should also be documented. This information can be obtained from topographical 

maps and geological maps, air photographs, airborne remote sensing, archeological records, state 

historical offices. libraries, real estate agencies, and mining records. Historical and archaeological sites 

that may include cultural resources should be identified and noted. Their presence may influence 

construction practices or site location. 

Current and historical records of human activities on the site can provide information such as withdrawal 

or addition fluids from or to the subsurface and the extraction of minerals. The location of abandoned 

mine workings such as adits, benches, shafts, and tailings embankments should be noted. 

Remote sensing surveys can provide additional information in many aspects, including interpretation of 

large scale and regional geologic structures, regional lineaments, drainage patterns, rock types, soil 

characteristics, erosion features, availability of construction materials, vegetation, surface water and 

changes in land use. Geologic features can be enhanced by manipulating remote sensing imagery. 

Detailed topographic maps can be produced from aerial photographs. Any problem boundaries or areas 

adjacent to the project that will be affected or affect the project in a negative way need to be identified so 

they can be modified, eliminated, or protected. 

1.2.2 Map Studies 

Various types of published maps, such as topographic, geologic, mineral resource, soils, and special 

miscellaneous maps. can be used to obtain geologic information and develop an understanding of the 

regional geology prior to the field reconnaissance and exploration work. The types of available maps and 

their description are presented in Table 1. Their uses are described in this section. 

1.2.2.1 Topographic Maps. Topographic and geologic maps can typically be found in the USGS 7-1/2 

minute series (1:24,000 or 1:25,000 scales) with contours and elevations in feet or meters respectively. 

Topographic maps are also available as 1:50,000, 1:100,000 and 1:250,000 series. The 15-minute series 

(1:62,500 scale) is not being updated by the USGS. Many of the 1:24,000 are available in digital raster 

form as DRG's, or digital raster graphs, and as DEM's, or digital elevation maps from USGS or 

commercial distribution. The 1:250,500 maps are available as DEM's and can be downloaded from the 

USGS web page. 

Availability information can be found at http://edcwww.cr.usgs.gov/nsdi/gendem.htm for Digital 

Elevation Models (DEM) and Digital Line Graphs (DLG), at ftp://www-nmd.usgs.gov/pub/ 

doi-high-priority/htmrldoq-stat.htmI for Digital Orthophoto Quadrangles (DOQ), and at 

http://mcmcweb.er.usgs.gov/drg/avail.html for Digital Raster Graphics (DRG). 

Topographic maps provide information about land forms, drainage patterns, slopes, locations of 

prominent springs and wet areas, quarries, man-made cuts (for field observation of geologic features and 

other man-made features), and mines. If older topographic maps are available, especially in mining

NUREG/CR-5738 12
1. Geologic Site Assessment

regions, abandoned shafts, filled surface pits, and other features can be located by comparison with 

current maps. 

Optimum use of topographic maps involves the examination of both large and small-scale maps. Certain 

features, such as large geologic structures, may be apparent only on small-scale maps. Conversely, the 

interpretation of locally active geomorphic processes will require accurate, large-scale maps with a small 

contour interval. As a general rule, the interpretation of topographic maps should proceed from 

small-scale (large area) maps through intermediate-scale maps to large-scale (small area) maps as the 

geologic investigation proceeds from the general to the more specific. 

Certain engineering geology information can be inferred from topographic maps by proper interpretation 

of land forms and drainage patterns. Topography tends to reflect the geologic structure, composition of 

the underlying rocks, and the geomorphic processes acting on them. The specific type of geomorphic 

processes and the length of time they have been acting on the particular geologic structure and rock type 

will control the degree to which these geologic features are evident on the topographic maps. Not all 

geologic features are equally apparent on topographic maps, and professional geologic knowledge is 

required to arrive at accurate geologic interpretations. Analysis of aerial photographs in combination 

with large-scale topographic maps is an effective means to interpret the geology and geomorphology of a 

site. Information of engineering significance that may be obtained or inferred from aerial photographs 

and topographic maps includes physiography, general soil and rock types, bedrock structure, and 

geomorphic history. 

1.2.2.2 Geologic Maps. Surficial and bedrock geologic maps can be used to identify geologic 

formations, formation contacts, gross structure, fault locations, and approximate depths to bedrock. 

Maps of 1:250,000 scale or smaller are suitable for the development of regional geology because they 

can be used with remote sensing imagery of similar scale to refine regional geology and soils studies. 

Large-scale geologic maps (1:24,000) are available for some areas (see Dodd, Fuller, Clarke, 1989, for 

instructions to access USGS publications). State Geologic surveys, local universities, state and federal 

DOT, and geotechnical and environmental firms may be able to provide detailed geologic maps of an 

area. Large-scale geologic maps provide information such as local faults, orientations of joints, detailed 

lithologic descriptions, estimates on depth to bedrock, and characteristics of surface and near-surface soil 

and rock. 

1.2.2.3 Mineral Resource Maps. Mineral resource maps produced by the USGS and state geological 

survey are important sources of geologic information. The USGS coal resources evaluation program, for 

example, includes preparation of geologic maps (7.5-min quadrangle areas) to delineate the quantity, 

quality, and extent of coal on federal lands. The USGS and state geological survey maps provide 

information on oil and gas lease areas and metallic mineral resource areas. Mineral resource maps also 

include information on natural construction materials such as quarries and sand and gravel deposits. 

These maps can be used in estimating the effects of proposed projects on mineral resources (such as 

access for future recovery, or reduction in project costs by recovery during construction). 

1.2.2.4 Hydrologic and Hydrogeologic Maps. Maps showing hydrologic and hydrogeologic 

information provide a valuable source of data on surface drainage, well locations, ground-water quality, 

groundwater level contours, seepage patterns, and aquifer locations and characteristics. The USGS 

(Dodd, Fuller, and Clarke, 1989, is an access guide for USGS information), state geological surveys, 

local universities, and geotechnical and environmental firms may provide this information.

13 NUREG/CR-5738
1. Geologic Site Assessment

1.2.2.5 Seismic Maps. Krinitzsky (1995) discussed the distribution of seismic source areas in the U.S. 

and provided a potential magnitude of earthquakes within each zone. Several World Wide Web sites are 

available as resources for seismic activity and history, including, but not limited to: 

http://wwwneic.cr.usgs.gov/ 

http://www.geophys.washington.edu/seismosurfing.html 

http://www.usgs.gov/network/science/earth/earthquake.html 

Peak acceleration and spectral acceleration (percent g) maps for various periods of ground motion have 

been generated by the USGS and others to assess seismic hazard. The Building Seismic Safety Council 

(BSSC) has published updated seismic hazard potential maps in the form of spectral values for periods 

0.1, 0.3 and 1.0 seconds. Ordering information for BSSC and national Institute of Building Sciences 

publications may be found on the World Wide Web at http://nibs.org/cato7.htm 

1.3 Walk-over Study 

The walk-over study provides a field verification of all the remote and documentary information 

collected during office studies. A multidisciplinary team should be formed at this stage to identify 

problem areas and design site-specific testing programs. The team leader is responsible for assuring that 

all pertinent information required is obtained to the desired level of detail. In general, the walk-over 

study should proceed from a regional approach initially to a site specific approach. 

1.3.1 Geologic Field Reconnaissance 

The walk-over study should include surface reconnaissance of the immediate site and surrounding areas. 

Detailed topographic, hydrologic, hydrographic, and surface geologic feature information should also be 

corroborated, corrected, and mapped. The identification of surface geologic features should include 

detailed onsite mapping of soils, and all surface water features present at the study site. Site 

accessibility, ground condition, and right of entry problems that could affect the exploration work must 

be identified as well as construction practices and existing structural distress that could indicate problem 

soil or rock conditions. Approximate soil profiles, representative samples of the principal strata, rock 

transects, or limited geologic cross sections by indirect methods of exploration should also be produced 

at this stage. The study of areas remote to the site may be necessary to have a more complete and 

reliable evaluation of the site. On-site observations and a fly-over by plane or helicopter would be an 

advisable approach for regional site mapping. The corroboration of previous geological interpretation of 

aerial photographs and other remote sensing imagery will provide a better visualization of the area. This 

approach can identify the need for new mapping or aerial photographic coverage. Such coverage should 

be coordinated with planners early in the study process to insure sufficient and timely coverage. 

An extensive photographic and video record taken by personnel with a background in geology or 

geotechnical engineering can serve as a reasonable proxy for cursory, preliminary investigations; 

however, a site visit by the site characterization team is essential. Potential environmental hazards such 

as former landfills, surface impoundments, mining activity, industrial sites, signs of underground storage 

tanks, distressed vegetation or dust should be recorded and assessed for Hazardous, Toxic, or Radioactive 

Waste (HTRW) potential. 

Figure 1 shows a diagram for the characterization of regional geology. This information will be the basis 

for further, more site-specific investigations. Field reconnaissance should be conducted at all sites that 

are potential facility locations and should include examination of important geologic features and

NUREG/CR-5738 14
1. Geologic Site Assessment

potential problem areas identified during office studies. Preliminary geologic, seismic, hydrologic, and 

economic studies should be used to indicate the most favorable sites before preliminary subsurface 

investigations are begun. Field observations have special value in planning subsequent investigations 

because adverse subsurface conditions often can be anticipated from surface evidence and regional 

geology. Proper coordination and timing of these studies, and incorporation into a GIS data base, can 

reduce costs and increase confidence in the results. 

Observations of geologic features should include rock outcrops and soil exposures to verify or refine 

available geologic maps. The strike and dip of major joint sets and evidence of adversely dipping beds 

that would affect the stability of natural or excavated slopes should be included. Indications of slope 

instability such as scarps, toe bulges, leaning trees, etc. should also be recorded. The locations of 

sources of construction materials, such as sand and gravel deposits, borrow areas for soils, and active or 

abandoned quarries are important. Observable hydrologic features include surface drainage flow, springs 

and seeps in relation to formation members, and marshy or thick vegetation areas indicating high 

groundwater tables. 

1.3.2 Geologic Field Mapping 

1.3.2.1 Areal Mapping. The purpose of areal mapping is to develop an accurate picture of the geologic 

framework of the project area. The area and the degree of detail to be mapped can vary widely 

depending on the type and size of project and on the regional geology. Map scales of 1:250,000, 

1:62,500 or 1:50,000 may be appropriate for small scale regional mapping and 1:24,000, 1:25,000, or 

larger scales are appropriate for more detailed and specific mapping. The area to be mapped should 

include the project site(s) as well as the surrounding area that could influence or could be affected by the 

project. 

Geologic and environmental features within the facilities' footprint and adjacent areas that should be 

studied and mapped include the following: 

• Faults, joints, stratigraphy, and other significant geologic features. 

"• Karst topography or other features that indicate potential for ground collapse. 

"• Water well levels, springs, surface water, water-sensitive vegetation, or other evidence of the 

groundwater regime. 

"* Presence of soluble or swelling rocks such as gypsum, anhydrite, or expansive clays 

"* Potential or old landslide areas. 

"* Archeological sites. 

"* Valuable mineral resources. 

"• Mine shafts, tunnels, and gas and oil wells. 

"• Potential borrow and quarry areas and sources of construction materials. 

• Shoreline erosion potential. 

• Landfills, dumps, underground storage tanks, surface impoundments, and other potential 

environmental hazards. 

Large-scale and detailed geologic maps should be prepared for specific sites of interest within the project 

area and should include proposed structure areas, borrow, and quarry sites. Investigation of the geologic 

features of overburden and bedrock materials is essential in site mapping and subsequent explorations.

15 NUREG/CR-5738
1. Geologic Site Assessment

CIVIL WORKS FEASIBILITY STUDIES 

GEOTECHNICAL INVESTIGATIONS 

DEVELOPMENT OF REGIONAL GEOLOGIC MODEL

DATA COLLECTION 

Interagency Coordination 

and Cooperation 

Sources of geologic, hydrologic, and soils 

data; insight into geologic hazards and 

HTRW problems; seismicity; construction 

materials; prior regional experience. 

Survey of Available 

Information 

Information similar to that obtained in 

Interagency coordination; published data on material properties; geologic conditions -

and history; known hazards; groundwater studies. 

Map Studies 

Formation descriptions and contacts; soil 

types and distributions; gross structure; 

fault locations; landforms, watersheds, 

slopes landslides; locations of springs, quarries, etc. 

Remote Sensing Studies 

Landforms; watersheds; lineaments; soil 

and rock type boundaries; outcrops; 

seeps; sinkholes; erosion features; vegetation, etc. 

Field Reconnaissances 

Ground truth for remote sensing; outcrop descriptions; site landforms and landscape position; soil depths and descriptions; springs; observable structure, bedding, and joints.

DATA ANALYSIS 

Distribution of Rock Types 

Transition from time-stratigraphic to 

grouping of rock materials by physical 

properties; definition of extent and 

magnitude of discontinuities. 

Distribution of Soil Types 

Equate geologiclsoil survey nomenclature -b

to engineering nomenclature. 

Geologic Structure 

Establish spatial distribution of rock . materials: locate major structural features; .. 

determine probable distribution of more detailed structural and textural; features. 

Geologic History 

Genesis of rock types; relationship to ._. significant physical properties; rock 

and soil depositional processes; geomorphic history. 

Seismicity 

Historical seismicity; locations and 

characteristics of probable capable faults; Spossible earthquake magnitudes in region; -4

possible intensities at candidate sites; 

preliminary selection of ground motions 

at candidate sites. 

Hydrogeology 

Regional groundwater flow patterns and 

water table depths; general hydraulic 

characteristics of subsurface materials; - -41 probable groundwater and seepage 

conditions at candidate sites; preliminary 

assessment of project impact on groundwater.

Construction Materials 

Existing sources in region located; "-• probable areas for development rock and soil borrow delineated.

Regional geologic and soils conditions established; preliminary assessments of 

seismicity and construction materials; tentative models of geologic and geomorphic 

conditions at potential sites developed; preliminary inputs into Environmental Impact Statements (EIS) 

and HTRW reports developed

Figure 1. Diagram for the development of regional geology

NUREG/CR-5738 16
1. Geologic Site Assessment

Determination of the subsurface features should be derived from a coordinated, cooperative study by 

geotechnical engineers and geologists. The geologist should contribute information on origin, 

distribution, and manner of deposition of the overburden and bedrock, and the geotechnical engineer or 

engineering geologist should determine the engineering properties of the site foundation, potential 

construction materials, the manner of application to design, and the adaptation of proposed structures to 

foundation conditions. 

1.3.2.2 Building Construction Sites. A preliminary map of geologic structure, lithology, and strati

graphy should be prepared prior to making any subsurface borings. For each proposed boring, an 

estimate should be made of the subsurface conditions anticipated, such as depths to critical contacts and 

to the water table. The process of progressively refining the model of the geologic structure and 

stratigraphy by comparison with boring information is the most efficient and cost-effective means to 

develop a complete understanding of the geologic site conditions for site characterization. 

1.3.2.3 Borrow and Quarry Sites. Sources of materials for embankment construction, riprap 

protection, and aggregates for concrete or road construction can often be located and evaluated during the 

regional mapping. It is sometimes necessary to expand the field area in order to locate suitable types and 

quantities of construction materials. In these instances, remote sensing techniques including analysis of 

aerial photography may be useful. Alternate plans that would utilize materials closer to the project but 

lower in quality should be tentatively formulated and evaluated. A complete borrow and quarry source 

map should include all soil and rock types encountered and adequate descriptions of surficial weathering, 

hardness, and joint spacings. 

Processed rock products are usually most economically acquired from commercial sources. Test results 

are often available on these sources through state or federal offices. Soil and/or rock sources should be 

selected based upon sampling and laboratory analysis. A geologic map may be used to determine 

material quantities available based on estimates of the depths and thicknesses of various deposits. 

Geologic maps can also be used to make a preliminary layout of haul and access roads in order to 

estimate haul distances. A GIS or similar system could be used to evaluate the quality and quantity of 

available quarry material, cost of excavation, and optimal transport routes. 

1.3.3 Construction Mapping 

Traditionally, these are geologic maps with details on structural, lithologic, and water-oriented features. 

They can represent planned structure foundations, cut slopes, and geologic features in tunnels or large 

chambers. These maps should be prepared to show any feature installed to improve, modify, or control 

geologic conditions. Some examples are rock reinforcing systems, permanent dewatering systems, and 

special treatment areas. The mapping of foundations is usually performed after the excavation has been 

cleaned to grade and just prior to the placement of concrete or backfill, to permit the observation and 

recording of geologic details in the foundation. Photographic and videographic record should be made 

during foundation mapping. 

The person in charge of foundation mapping for critical structures should be familiar with design intent 

via careful examination of design memoranda and discussion with design personnel. The actual geology 

should be compared with the geologic model developed during the design phase to evaluate whether or 

not there are any significant differences and how these differences may affect structural integrity. The 

person in charge of foundation mapping should be involved in all decisions regarding foundation 

modifications or additional foundation treatment considered advisable based on conditions observed after 

preliminary clean-up. Design personnel should be consulted during excavation work whenever

17 NUREG/CR-5738
1. Geologic Site Assessment

differences between the actual geology and the design phase geological model require clarification or 

change in foundation design. Mapping records should include details of all foundation modifications and 

treatment performed. 

Appendix A provides detailed guidance on technical procedures for mapping foundations. Mapping of 

tunnels and other underground openings must be planned differently from foundation mapping. Design 

requirements for support of the openings may require installation of support before an adequate cleanup 

can be made for mapping purposes. Consequently, mapping should be performed as the heading or 

opening is advanced, and during the installation of support features. This requires a well trained 

geologist, engineering geologist, or geological engineer at the excavation at all times. Specifications 

should be included in construction plans for periodic cleaning of exposed surfaces and to allow a 

reasonable length of time for mapping to be carried out. Technical procedures for mapping tunnels are 

outlined in Appendix B and can be modified for large chambers. 

1.3.4 Remote Sensing Methods 

Conventional aerial photographs and various types of satellite and other aerial imagery can be used 

effectively for small-scale regional interpretation of geologic structure, analyses of regional lineaments, 

drainage patterns, rock types, soil characteristics, erosion features, and availability of construction 

materials. Geologic hazards, such as faults, fracture patterns, subsidence, and sink holes or slump 

topography, can be recognized from stereoscopic examinations of air photo pairs and imagery 

interpretation. Detailed topographic maps can be generated from aerial stereophotography that has 

sufficient surveyed ground control points. Remote sensing images that are in digital format can be 

processed to enhance geologic features (Gupta, 1991). Although it is normally of limited value to site 

specific studies, satellite imagery such as Landsat, Sky Lab, and French SPOT images are useful for 

regional studies. 

Gupta (1991) provides more detailed discussions of remote sensing techniques and their application to 

geotechnical investigations. Additional information concerning remote sensing surveying of bathymetry 

can be obtained in EM 1110-2-1003 (DA, 1995). 

Spatial components typically used to prepare a GIS reference base map include: topographic maps, aerial 

photographs (digital orthophotos), monumentation/survey control maps, surface/subsurface geology 

maps, land use maps, bathymetry maps, and various forms of remotely sensed data. Project-specific 

planimetric maps or digital elevation models (DEM' s) are generated through photogrammetric methods 

and can be displayed using a GIS. A DEM may be used to interpolate and plot a topographic contour 

map, generate 2-dimensional (contour or shaded relief) or 3-dimensional (perspective) views of the 

modeled surface, determine earthwork quantities, and produce cross-sections oriented along arbitrary 

alignments. 

Geotechnical parameters resulting from surface and subsurface explorations can be referenced to a 

Digital Terrain Model (DTM), resulting in a spatial database capable of producing geologic cross

sections, and 2- and 3-dimensional strata surface generation. Georeferencing spatial data requires that 

the information be precisely located. Global Positioning system (GPS) techniques offer a rapid and 

reliable way to accomplish this (EM 1110-1-1003). Even with a GPS, however, surveyed monuments 

and benchmarks must be identified and used as control points in the survey. Benchmark and brass cap 

information is available through the National Geodetic Survey of NOAA for the entire U.S.

NUREG/CR-5738 18
2. Groundwater Investigations

A GIS can be used to streamline and enhance regional or site-specific geotechnical investigations by: 

(1) Verifying which information is currently available and what new data must be obtained or generated 

to fulfill requirements for the desired level of study. (2) Sorting and combining layers of information to 

evaluate the commonality of critical parameters and compatibility of proposed alternatives/sites, and 

(3) Assigning quantitative values and relational aspects of data combinations and classifications. In this 

respect, a geotechnically augmented GIS database can be used to quantify reliability and uncertainty for 

specific design applications and assumptions. Burrough (1986), Intergraph (1993), and Kilgore, Krolac, 

and Mistichelli (1993) provide further explanations of GIS uses and capabilities. 

2 GROUNDWATER INVESTIGATIONS 

2.1 General 

Groundwater investigations produce information that may be vital to selection of foundation sites and 

should be required in site characterization programs for large, complex facilities. The objectives and 

level of detail required should be determined early in the study to identify the data requirements and the 

resources needed to produce the information. Guidance for development of a conceptual model of a field 

site and selection of an analytical test method for determination of hydraulic properties is provided in 

ASTM D 4043-96, 1996, "Guide for Selection of Aquifer Field Test and Analytical Procedures in 

Determination of Hydraulic Properties by Well Techniques." 

For engineering foundation projects, records of groundwater levels, pressures, seasonal variations, and 

the relationship of groundwater with surface waters or tides should be evaluated. Borings, wells, and 

piezometers must be correctly located and accurately surveyed for reliable groundwater investigations. 

Table 3 describes instruments to measure groundwater pressure (Dunnicliff, 1988). The kinds of 

information that can be obtained from groundwater studies include: position and thickness of aquifers 

and confining beds (aquicludes), transmissivity, storage coefficient, location and nature of aquifer 

boundaries, and hydraulic characteristics of aquicludes. Piezometers, when correctly chosen and 

installed, can monitor groundwater flow patterns, directions, and velocities. Instrument calibration, 

maintenance, and recalibration are necessary to assure proper performance of the systems and reliable 

results. 

The scope of groundwater studies is determined by the size and nature of the proposed project. The type 

of studies can range from broad regional studies at a reservoir project to site-specific studies such as 

pumping tests for relief well design, water supply at a recreational area, or pressure tests performed to 

evaluate the need for foundation grouting. ASTM D 5474-93, 1993, "Guide for Selection of Data 

Elements for Groundwater Investigations," explains the logic of why individual and combinations of data 

elements are selected to meet the requirements of the study (with examples of specific groundwater 

investigations). Groundwater studies include observations and measurements of flows from springs and 

of water levels in existing wells, boreholes, selected observation wells, and piezometers. This 

information is used with site and regional geologic information to determine water table elevations and 

profiles, fluctuations in water table elevations, the possible existence and location of perched water 

tables, depths to water-bearing horizons, direction and rate of seepage flow, and potential for leakage 

from a proposed reservoir or beneath an embankment or levee. Results from groundwater and foundation 

seepage studies provide data needed to design dewatering and seepage control systems at construction 

projects, indicate the potential for pollution and contamination of existing groundwater resources due to

19 NUREG/CR-5738
Table 3 Instruments for Measuring Groundwater Pressure (Dunnicliff, 1988, reprinted by permission of John Wiley & 

Sons, Inc.) 

Instrument Type Advantages Limitations'

Observation well

9 

-. 1 

00

Open standpipe piezometer 

Twin-tube hydraulic piezometer 

Pneumatic piezometer 

Vibrating wire piezometer 

Unbonded electrical resistance piezometer

Can be installed by drillers without participation of 

geotechnical personnel. 

Reliable. 

Long successful performance record. 

Self-de-airing if inside diameter of standpipe is adequate. 

Integrity of seal can be checked after installation. 

Can be converted to diaphragm piezometer. 

Can be used for sampling groundwater. 

Can be used to measure permeability. 

Inaccessible components have no moving parts. 

Reliable. 

Long successful performance record. 

When installed in fill, integrity can be checked after 

installation. 

Piezometer cavity can be flushed. 

Can be used to measure permeability. 

Short time lag. 

Calibrated part of system accessible. 

Minimum interference to construction: level of tubes and 

readout independent of level of tip. 

No freezing problems. 

Easy to read. 

Short time lag. 

Minimum interference to construction: level of lead wires 

and readout independent of level of tip. 

Lead wire effects minimal. 

Can be used to read negative pore water pressures. 

no freezing problems. 

Easy to read. 

Short time lag. 

Minimum interference to construction: level of lead wires 

and readout Independent of level of tip. 

Can be used to read negative pore water pressures. 

No freezing problems. 

Provides temperature measurement. 

Some types suitable for dynamic measurements. 

(Continued)

Provides undesirable vertical connection between strata and is 

therefore often misleading; should rarely be used. 

Long time lag. 

Subject to damage by construction equipment and by vertical 

compression of soil around standpipe. 

Extension of standpipe through embankment fill interrupts 

construction and causes inferior compaction. 

Porous filter can plug owing to repeated water inflow and outflow. 

Push-in versions subject to several potential errors. 

Application generally limited to long-term monitoring of pore water 

pressure in embankment dams. 

Elaborate terminal arrangements needed. 

Tubing must not be significantly above minimum piezometric 

elevation. 

periodic flushing may be required. 

Attention to many details is necessary. 

Attention must be paid to many details when making selection. 

Push-in versions subject to several potential errors. 

Special manufacturing techniques required to minimize zero drift. 

Need for lightning protection should be evaluated. 

push-in version subject to several potential errors. 

Low electrical output. 

Lead wire effects. 

Errors caused by moisture and electrical connections are possible. 

Need for lightning protection should be evaluated.

tO) O

0 

0t 

o
Table 3 (Concluded) 

Instrument Type Advantages Limitations' 

Bonded electrical resistance piezometer Easy to read. Low electrical output. 

Short time Iag. Lead wire effects. 

Minimum interference to construction level of lead wires Errnrs caused by moisture, temperature, and electrical 

and readout independent of level of tlp connections are possible. 

Suitable for dynamic measurements Long term stability uncertain. 

Can be used to read negative pore water pressures. Need for lightning protection should be evaluated. 

No freezing problems. Push-in version subject to several potential errors. 

Multipoint piezometer, with packers Provides detailed pressure-depth measurements. Limited number of measurement points. 

Can be installed in horizontal or upward boreholes. Other limitations depend on type of piezometer: see above in 

Other advantages depend on type of piezometer: see table. 

above in table. 

Multipoint piezometer, surrounded with Provides detailed pressure-depth measurements. Limited number of measurement points. 

grout Simple installation procedure. Applicable only in uniform clay of known properties. 

Other advantages depend on type of piezometer: see Difficult to ensure in-place grout of known properties. 

above in table. Other limitations depend on type of piezometer: see above in 

table. 

Multipoint push-in piezometer Provides detailed pressure-depth measurements. Limited number of measurement points. 

Simple installation procedure. Subject to several potential errors. 

Other advantages depend on type of piezometer: see Other limitations depend on type of piezometer: see above in 

above in table. table. 

Multipoint piezometer, with movable Provides detailed pressure-depth measurements. Complex installation procedure. 

probe Unlimited number of measurement points. Periodic manual readings only. 

Allows determination of permeability. 

Calibrated part of system accessible. 

Great depth capability. 

Westbay Instruments system can be used for sampling 

groundwater and can be combined with inclinometer 

casing. 

'Diaphragm piezometer readings indicate the head above the piezometer, and the elevation of the piezometer must be measured or estimated if piezometric elevation is 

required, All diaphragm piezometers, except those provided with a vent to the atmosphere, are sensitive to barometric pressure changes.

1-.

LI' 

-.1 rJ

00

5n 

0 

-I 

W 

Cn
2. Groundwater Investigations

project operation, show potential for interference to aquifers by the construction of a project, and 

determine the chemical and biological quality of groundwater and its relationship to project 

requirements. Investigation and continued monitoring of groundwater fluctuations are key issues for 

retention ponds and dam safety. ASTM D 5447-93, 1993, "Guide for Application of Ground Water Flow 

Model to a Site Specific Problem," covers the application and documentation of a groundwater flow 

model to a particular site or problem, simulating or reproducing an aquifer studied in the field. The 

concepts are applicable to a wide range of models designed to simulate subsurface processes. 

2.2 Methods of Observation 

The following is a list of available tools for assessment of local and regional groundwater investigations. 

2.2.1 Wells 

Existing wells located during field geologic reconnaissance should be sounded, or water levels obtained 

from the well owners. The well location and the elevation of the top of the well should be checked for 

accuracy. Pumping quantities, seasonal variations in groundwater and pumping levels, depths of wells 

and screen elevations, corrosion problems, and any other relevant information should be acquired 

wherever available. Any settlement records attributable to groundwater lowering from pumping should 

be obtained. This information should be compared with water well records obtained during preliminary 

studies to develop a complete hydrologic picture for the project area. ASTM D 5092-95, 1995, 

"Practices for Design and Installation of Groundwater Monitoring Well in Aquifers," provides guidance 

on the design and installation of groundwater monitoring wells to obtain representative and reliable 

information, once a site specific conceptual model has been developed. 

2.2.2 Borings 

Water levels recorded on drilling logs are another source of information. They may not reflect true water 

levels, however depending on soil types and time of reading after initial drilling. The influence of 

drilling fluids on water level readings should be kept in mind when evaluating boring data. Loss of 

drilling fluids can indicate zones of high permeability. Where groundwater level information is needed, 

installation of piezometers or observation wells in borings should be considered. 

2.2.3 Piezometers and Observation Wells 

The most reliable means for determining groundwater levels is to install piezometers or observation 

wells. All information developed during preliminary studies on the regional groundwater regime should 

be considered in selecting locations for piezometers and observation wells. Useful references for types 

of piezometers, construction details, and sounding devices include: EM 1110-2-1908, Part 1 

(Department of the Army (DA), 1995) and U.S. Departments of the Army, Navy, and Air Force (1983). 

All piezometer borings should be logged carefully, and "as built" sketches prepared that show all 

construction and backfill details (e.g., Figure 2). 

The selection of the screened interval is critical to the information produced since the water level 

recorded will be that associated with the highest of all intervals within the screen/filter length. Careful 

evaluation of the conditions encountered in the hole with regard to perched or confined aquifers is 

essential to selection of the screened interval and interpretation of the data. One of the greatest benefits 

of a piezometer or observation well is that it permits measurement of fluctuations in piezometric levels

NUREG/CR-5738 22
2. Groundwater Investigations

DRILLING LOG DIVISION: CLIENT: SHEET 1 

ENVIRONMENTAL ENGINEERING U.S. ARMY- APG D.S.H.E-E.M.D 0F2 SHEETS 

1. PROJECT: S. SCREENED INTERVAL: SCREEN TYPE GALVINIZED STEEL 

FTA WESTERN BOUNDARY INVESTIGATION 45.0-50.0 FT 0.010 IN CONTINUOUS SLOT 

2. LOCATION: MSPCS: 656,502 NORTHING 9. SAMPLING METHOD (SOIL) (AIR) 

WB-P1 1,541,174 EASTING 2.0 FT SPLIT SPOON : PHOTOVAC MICROTIP HL2000 

3. COUNTY: STATE: 10. DRILLING EQUIPMENT: HARFORD MARYLAND GUS PECH E BRAT 22R 

4. HOLE NO. (AS SHOWN IN STATERECORDS) 11. ELEVATION GROUNDWATER (MEASURED FROM GROUND LEVEL) 

HA-92-0494 10.7 FT MSL 

5. NAME OF DRILLER: 12. DATE HOLE: :STARTED: : COMPLETED: 

JAMES MARSH 14 OCT 92 : 15 OCT 92 

6. DRILLING AGENCY: 13. ELEVATION OF TOP OF HOLE: iTOP OF RISER 

LAYNE ENVIRONMENTAL SERVICES 40.70 FT 43.41 FT 

7. DEPTH OF HOLE NAME OF INSPECTOR 

77.0 FT MARK A. LEWIS 

- , r -I-I , T I -

DEPTH CLASSIFICATION OF MATERIALS ILOW 

FEET (DESCRIPTION) uscs ICOUNTS

Light brown sandy silt 

Brown siity fine to med. send With 

trace rue ae•v•s. "Jan9.1 SM 

White to tin Ine san"d, pomly soled S P 

Tan silty fine sand, seubangar SM 

Tan fine lo coarse snds, pooly soed SP 

Bron ,sandy day, sightly piasfc SC 

Brown medium to coarse poity sarted 

send with s.•e fine graMvelS. subecunded 

Light brown silty clay, 

slight to medium plasticity 

CL 

Yenooisid orange ilty fine 

sand. subangUa8r SIM 

Brown sandy day. medium pIastcty SC 

Light brown fine sand, 

subrounded

SP

5

10 

15-

20~ 

25= 

30

35

40-

45=

WVELL LITHOLOGY COMPLETION 

DLAGRAM

w 

(0 

z 

z 

FQ

7/

S.. . . DE.PTH

("dJng unm, wator los,. depot o weaueUfkrl, ec., 1I'fgr•r'nQ FEET 

Above Ground 

Completion 

-5 

- 20:1 Portland Cement 

Bentonite Grout 

10 

15 

20 

25 

30 

No Organic Vapor Readings 

Above Background in 

Breathing Zone -35 

- Bentonite Slurry Seal 

40 

- Filter Pack #2 Sand -- 45

Figure 2. Example of report quality log with lithologic, blow count, moisture, and well completion 

information. 

23 NUREG/CR-5738

I ____________________

1-4'le I ý ý ý
2. Groundwater Investigations

over time. To take advantage of this benefit, it is necessary to provide for periodic readings. This can be 

accomplished through manual reading or with an automated system, depending on the location and 

critical importance of the area being monitored. 

Time Domain Reflectometry (TDR) offers a tool for groundwater elevation measurement within very 

small boreholes. TDR refers to techniques wherein short pulses of energy generated by an 

electromagnetic source are reflected back to the source by an anomaly (radar is an early example of TDR 

technology,, TDR technology used for monitoring groundwater elevations is essentially a closed circuit 

radar). An electrical pulse is sent down a coaxial cable and is reflected by a change in cable capacitance 

caused by the air/water interface. The distance between the pulse source and the water is calculated from 

the average of the measured pulse travel time and the pulse velocity. Borehole diameter required to 

accommodate the diameter of the cable may be quite small, and the cable may be left in place, 

eliminating the need for decontamination of the equipment between readings on sites where this feature 

is desired. 

Other information that can derived from observation wells and piezometers are temperature and water 

quality data. Tracer tests can sometimes be done, if there is enough time and the aquifer is sufficiently 

transmissive. to determine the direction and rate of groundwater flow. 

2.2.4 Springs and Surface Water 

The water elevation, flow rate, and temperature of all springs located within the project area should be 

measured. Water should be sampled for chemical analysis to establish a base level. Soil or rock strata at 

the spring should be evaluated to locate permeable horizons. Flow rates at springs should be measured 

during drv. and wet seasons to determine the influence of rainfall on seepage conditions. The elevation of 

water levels in lakes and ponds should be measured during the wet and dry seasons to evaluate the extent 

of surface •vater fluctuations. 

2.2.5 Tracer Testing 

In some areas, especially karst terrains, it is of particular interest to determine preferential flow paths in 

the groundwater system. Flow paths can be evaluated by conducting tracer tests using either 

environmentally benign dyes or biological tracers such as pollen. The tracer element is introduced into a 

boring or other aquifer access points and monitored at exit points such as springs. The travel time from 

introduction to detection is recorded. Numerous tests can be run at different locations and times to 

interpret the overall groundwater flow regime. Tracer tests can be either qualitative or quantitative. 

2.2.6 Geophysical Methods 

Geophysical methods, such as seismic refraction, can be used to determine the depth to saturated 

material. Surface resistivity and ground penetrating radar surveys can also indicate the presence of and 

depth to water (Annan, 1992). Fetter (1988) discusses the application of these and other geophysical 

methods to characterize the hydrology and hydrogeology of a site. Geophysical survey techniques 

applicable to geotechnical site characterization are presented in Section V.

NUREG/CR-5738 24
2. Groundwater Investigations

2.3 Permeability Testing 

Permeabilities and transmissivities of foundation materials can be determined from tests in piezometers 

and wells (pumping tests and slug tests), laboratory tests on undisturbed samples, and pressure tests in 

rock foundations. The permeability of sands can be roughly estimated based on (the D10 size) the size of 

particle in a particular gradation for which 10 percent, by weight, of particles are finer (TM 5-818-5). 

Fracture and joint analysis is important in evaluating permeability of rock foundations. In situ tests for 

permeability are preferred over laboratory tests since it is very difficult to obtain accurate or 

representative formation permeability values from laboratory samples and testing. Permeability tests can 

be performed for rocks or soils, in boreholes, piezometers, or by sealing drillhole sections. The most 

commonly used tests are the rising and falling head tests, the constant head tests, and the packer or 

Lugeon tests, which sample the borehole point and the immediate surroundings. To evaluate the 

groundwater behavior of a larger area in a comprehensive way, pumping tests addressing the whole 

formation are performed and analyzed using the time-drawdown and distance-drawdown pumping 

methods. Permeability in soils is an anisotropic property; vertical and horizontal permeabilities may 

differ greatly and must be independently measured. Groundwater flow models must account for this 

anisotropy. General reviews of methods to evaluate permeability of soil and rock in the subsurface are 

given by Heath (1983) and Fetter (1988). 

2.3.1 Tests in Piezometers or Wells 

Permeability tests can be made in piezometers or wells. They should be performed as part of piezometer 

installation procedures, both to obtain permeability information and to assure that the piezometer is 

working satisfactorily. In a slug test a "slug," or fixed quality, of water or of a solid is either added to or 

removed from the well. The information obtained is representative of a smaller volume of material than 

that tested in well pumping tests. However, procedures are simple, costs are low, and results may be 

useful if interpreted with discretion and if tests are performed in several wells. Test details are discussed 

in EM 1110-2-1908, Part 1 (DA, 1995); TM 5-818-5 (U.S. Departments of the Army, the Navy, and the 

Air Force, 1983); U.S. Department of Interior (1977), Mitchell, Guzikowski, and Villet (1978); and 

Bennett and Anderson (1982). 

The rising or falling head (slug test) tests are performed on relatively permeable soils in either a cased 

borehole or a piezometer. To analyze the results of these tests, the Hvorslev basic time lag concept and 

method maybe used (Hvorslev, 1949). There are also other methods available for different well 

geometries. 

The constant head testing technique is used for soils susceptible to consolidation or swelling with stress 

changes. In-situ permeability tests performed in clays sometimes will render higher permeability values 

than actually exist due to the swelling of certain clays when exposed to increased pore water pressure. 

The purpose of a constant head permeability test is to determine the flow rate under steady seepage 

conditions after swelling has occurred. Hydraulic fractures may result from the use of high pressures 

during this kind of test; vertically in normally consolidated soils, and horizontally in overconsolidated 

soils. The development of these cracks will produce a sudden rise in permeability rates, several orders of 

magnitude higher than that of the intact material. 

The packer or "Lugeon" test is the rock equivalent of the constant head permeability tests for soils. The 

test can be performed by sealing the test section at the bottom of a drill hole with a single packer 

(Figure 3-a), or at any depth by sealing the section with a double packer (Figure 3-b). Generally these 

tests are performed in vertical boreholes, but tests in other borehole orientation can be used to estimate

25 NUREG/CR-5738
2. Groundwater Investigations

TER

PACKER

S2r, sGROUNDWATER TABLE 

7_ t 7 

a, SINGLE PACKER TECHNIQUE 

PRESSURE GAGE 

OýLFL OWMETER

PAC.KERS

GROUNDWATER TABLE 

R2 . 2 r 

b. DOUBLE PACKER TECHNIQUE

Figure 3. Single packer and double packer techniques (RTH).

NUREG/CR-5738 26
2. Groundwater Investigations

rock mass anisotropy. A number of factors need to be taken into consideration when performing these 

tests, such as the possibility of packer leakage, material disturbance from the drilling process, erosion or 

distension of fractures, turbulent flow, siltation due to the use of dirty water, and the effect of performing 

the test above the groundwater level. Suggested method, test protocol and data reduction for these tests 

can be obtained in RTH 381-80, "Suggested Method for in Situ Determination of Rock Mass 

Permeability Using Water Pressure Tests." 

2.3.2 Pumping Tests 

Pumping tests are the traditional method for determining permeability of sand, gravels, or rock aquifers 

below the water table. The test consists of pumping a well at a constant rate for a period of time ranging 

from several hours to several days and measuring the change in water level in observation wells located 

at different distances from the pumped well. The drawdown is the difference between the water level at 

any time during the tests and the position of the static water level. For example, a pump test for an 

unconfined aquifer is typically run for 72 hours; confined aquifers may require 24-hour tests; and 8 to 

24 hours can suffice for low capacity tests (less than 10 gpm). Piezometers or monitoring wells should 

be installed to measure the initial and lowered groundwater levels at various distances from the pumped 

well. Piezometers should have a point intake, no more than a few inches in length, through a porous tip. 

Monitoring wells may have screened intakes, several feet in length. At known or suspected HTRW sites, 

disposal of pumped water is a major consideration. For details of pumping tests and analyses, refer to 

TM 5-818-5. Pumping tests are usually desirable for the following: 

"* Large or complex projects requiring dewatering. 

"• Design of underseepage systems for dams or levees. 

"• Special aquifer studies. 

"• Projects where water supply will be obtained from wells. 

"• Projects immediately downstream from existing embankments. 

Pumping tests evaluate the groundwater aquifer over an extensive area. The kinds of information that 

can be obtained from pumping tests include: position and thickness of aquifers and confining beds (from 

boring information), hydraulic conductivity, transmissivity, storage coefficient, yield, location and nature 

of aquifer boundaries, hydraulic characteristics of confining beds, and identification of the types of 

aquifer (confined or unconfined). They are essential to characterizing groundwater behavior in a 

formation in a three-dimensional and comprehensive way. A pumping test monitors change in water 

levels in a well or observation wells over time in an aquifer caused by withdrawal from (drawdown test) 

or recharge to (recovery test) a well. 

Several methods are available to analyze pumping test data. Theis (1935) analyzed radial flow to a 

pumped well in confined aquifers using heat flow analogies; curves developed from Theis' work can be 

used to analyze the data obtained from the drawdown test. The Theis method permits prediction of the 

drawdown curve in non-equilibrium (non-steady) conditions by taking into account the effect of pumping 

time on the amount of water removed, or yield. Modifications of the Theis method have been developed 

to allow a simple analytical determination of aquifer properties without the tedious curve-matching of the 

Theis method, although computer assisted analyses are now available that make the curve matching 

techniques much easier. Some examples follow: 

2.3.2.1 Time-drawdown Test. This test involves a modification of the Theis equation whereby under 

certain simplifying assumptions the time-drawdown curve (the shape of the drawdown phreatic surface) 

is used to calculate aquifer coefficients. This approach, called the Jacob method (Cooper and Jacob,

27 NUREG/CR-5738
2. Groundwater Investigations

1946), works with both time-drawdown and distance-drawdown procedure. It works under the same 

assumptions of the Theis equation and is sensitive to the changes in shape that occur in the cone of 

depression during an aquifer tests and changes in the drawdown rate. The Jacob method is applicable 

only to the portion of the drawdown surface in which steady-shape conditions prevail or to the entire 

cone of depression only after steady-state conditions have developed (Heath, 1983). 

2.3.2.2 Distance-drawdown Test. To perform this kind of test at least three observation wells at 

different distances from the pumping well are necessary. Drawdown measurements are taken at the same 

time from the different wells and then analyzed with the Theis equation or the Jacob method to determine 

the aquifer transmissivity and storage coefficient. The Jacob method can be utilized with a time

drawdown graph, using data from an individual well, or with a distance-drawdown graph using multiple 

"simultaneous" measurements from all the wells (Heath, 1983). 

2.3.3 Permeability of Rock 

Most rock formations contain complex interconnecting systems of joints, fractures, bedding planes, and 

fault zones that, collectively, are capable of transmitting groundwater. This fracture or joint permeability 

is normally several magnitudes higher than the matrix permeability of the discrete blocks or masses of 

rock contained between the joints. The permeability of some rock masses, such as sandstones and 

conglomerates, is governed by interstitial voids similar to those in soils. Secondary weathering and 

solutioning of limestones and dolostones may produce large void spaces and exceptionally high 

permeabilities. Although the permeability of rock results from interconnecting systems of joints, 

fractures, and formational voids, the equivalent rock mass permeability can frequently be modeled as a 

uniform porous system. Although it is necessary to keep the hydrologic model manageable, the 

shortcoming of this approach is that most rock masses, like soil deposits, are anisotropic with regard to 

permeability. The influence of anisotropy on a practical level is that it is easy to over- or underestimate 

the groundwater effects in rock. As an example, if a pumping test is conducted with monitoring wells 

oriented along a line perpendicular to the predominant water-bearing joint set, the results will 

underestimate the radius of influence along the joint set. Therefore, the layout of pumping tests must be 

well thought out beforehand. 

At least preliminary fracture and joint analysis should be conducted prior to laying out a pump test. 

Because joint or fracture permeability frequently accounts for most of the flow of water through rocks, an 

accurate description of in-situ fracture conditions of a rock mass is critical to predicting performance of 

drains, wells, and piezometer responses. Joints typically occur in sets which have similar orientations. 

There may be three or more sets of joints in a rock mass. Joint sets which occur in the rock mass at the 

site should be identified and the preferred orientation and range in orientation of each joint set recorded. 

Features such as joint orientation, spacing, joint width, and the degree and type of secondary mineral 

filling should be carefully noted for each joint set. Once all joint sets of a site have been identified and 

evaluated, their relative importance to groundwater flow should be assessed. 

2.3.4 Pressure Tests 

Pressure tests are performed to measure the permeability of rock masses. Pressure test results are used in 

assessing leakage in the foundation and as a guide in estimating grouting requirements. Pressure tests are 

typically conducted during exploratory core drilling and are a relatively inexpensive method of obtaining 

important hydrogeologic information about a rock mass. Hydraulic pressure testing should be considered 

an integral part of the exploratory core drilling process in all cases where rock seepage characteristics 

could affect project safety, feasibility, or economy. The testing interval is typically 5 tol0 ft but may be

NUREG/CR-5738 28
3. Borings and Exploratory Excavations

varied to fit specific geological conditions observed during the core drilling operations. Zones to be 

tested should be determined by (a) examining freshly extracted cores, (b) noting depths where drill water 

was lost or gained, (c) noting drill rod drop, (d) performing borehole or TV camera surveys, and 

(e) conducting downhole geophysical surveys. In rock with vertical or high angle joints, inclined borings 

are necessary to obtain meaningful results. Types of tests and test procedures are described in Ziegler 

(1976), U.S. Department of Interior (1977), and Bertram (1979). 

Pressures applied to the test section during tests should normally be limited to 1 psi/ft of depth above the 

piezometric level and 0.57 psi/ft of depth below the piezometric level. The limit was established to avoid 

jacking and damage to rock formations. The limit is conservative for massive igneous and metamorphic 

rocks. However, it should be closely adhered to for tests in horizontally bedded sedimentary and other 

similar types of formations. Naturally occurring excess water pressures (artesian) should be taken into 

account in computations for limiting test pressures. Where the test intervals are large, a reduction in total 

pressure may be necessary to prevent jacking of the formation within the upper portion of the test 

section. 

An important but often unrecognized phenomenon in pressure testing is joint dilation and contraction as 

pressure is applied and released. In the case of a dam project, it is desirable to use pressures that will 

correspond to future reservoir conditions. Joint dilation can frequently be observed by conducting a 

"holding" test. The fall in pressure is observed and a plot of pressure versus time is made. The pressure 

should quickly drop to near the surrounding piezometric level if the joint openings remain the same 

width. The common observation of a slow pressure decay in pressure holding tests indicates joint 

closure with reduction in pressure. 

Qualitative evaluations of leakage and grout requirements can be made from raw pressure test data 

(Zeigler, 1976; U.S. Department of Interior, 1977; Bertram, 1979). Most analyses of this type assume 

laminar flow rather than turbulent flow. This assumption can be verified by conducting pressure tests on 

the same interval at several different pressures. If the water take is directly proportional to the total 

applied pressure, laminar flow can be assumed. If pressure test data are converted into values of 

equivalent permeability or transmissivity, calculations can be performed to estimate seepage quantities. 

Wherever possible, such results should be compared with data from completed projects where similar 

geologic conditions exist. 

3 BORINGS AND EXPLORATORY EXCAVATIONS 

3.1 Borings 

Borings are required to characterize the geologic materials and subsurface characteristics beneath 

planned foundations. Borings and borehole samples are used to identify and classify soil type, determine 

engineering properties, describe soil strata or rock, and assess solution and void conditions. The drilling 

method used to advance the borehole will depend on its applicability to the specific ground conditions 

and the purpose of the boring. Boring types might be rotary, percussion, and drive (or push). Sampling 

methods are classified broadly as disturbed, undisturbed, and core and are discussed in Section IV. Some 

major uses for borings are as follows. 

• Define geologic stratigraphy and structure.

29 NUREG/CR-5738
3. Borings and Exploratory Excavations

"* Obtain samples for index testing. 

"• Obtain groundwater data. 

"• Perform in-situ tests (see Section V for geophysical tests and Section VI for penetration and other 

in situ tests). 

"* Obtain samples to determine engineering properties. 

"• Install instrumentation. 

"* Establish foundation elevations for structures. 

"* Determine the engineering characteristics of existing structures. 

Borings are frequently used for more than one purpose, and it is not uncommon to use a boring for 

purposes not contemplated when it was made, and thus it is important to have a complete log of every 

boring, even if there may not be an immediate use for some of the information. If there is doubt 

regarding the range of sizes for borehole use, or insufficient information to determine optimum borehole 

size, then the hole should be drilled larger than currently thought needed. A slightly larger than needed 

borehole is considerably less expensive than a second borehole. 

A major part of field investigations is the compilation of accurate borehole logs on which subsequent 

geologic and geotechnical information is based. A field drilling log for each borehole can provide an 

accurate and comprehensive record of the lithology and stratigraphy of soils and rocks encountered in the 

borehole together with any other relevant information obtained during drilling, sampling, and in-situ 

testing. To accomplish this objective, an experienced geologist, soils engineer, or civil engineer with 

good geotechnical training and experience should be present during drilling. The duties of the field 

inspector include the following: 

"* Observing and describing drilling tools and procedures. 

"• Observing, classifying, and describing geologic materials and their discontinuities. 

"* Selecting and preserving samples. 

"* Performing field tests on core samples (hand penetrometer, torvane). 

"* Photographing site conditions and cores. 

"* Observing and recording drilling activities and groundwater measurements. 

* Overseeing and recording instrument installation activities. 

"* Completing the drilling log and/or entering information into a cataloging system. 

"* Recording information and data from in-situ tests. 

The logs of borings are normally made available to contractors for use in preparing their bids. The 

descriptions contained on the logs of borings give the contractor an indication of the type of materials to 

be encountered and their in-situ condition. Special care must be taken to ensure a clear differentiation on 

logs between field observations and laboratory test results. Guidance on soil identification and 

description, coring, and core logging is provided in the remainder of this section. 

3.1.1 Boring Methods 

Many methods are used to make borings; some of the more common methods are discussed in the 

following paragraphs. Many of these are also discussed in detail in EM 1110-1-1906 (DA, 1996) and 

Das (1994). Some factors that affect the choice of methods are: 

"• Purpose and information required. 

"* Equipment availability. 

"* Depth of hole.

NUREG/CR-5738 30
3. Borings and Exploratory Excavations

"• Experience and training of available personnel. 

"° Type of materials anticipated. 

"• Terrain and accessibility. 

"* Cost. 

"° Environmental impacts. 

"• Disruption of existing structures. 

3.1.1.1 Auger Borings. Auger borings provide disturbed samples that are suitable for determining soil 

type, Atterberg limits, Proctor compaction testing, and other index properties but generally give limited 

information on subsoil stratification, consistency, or sensitivity. Auger borings are most useful for 

preliminary investigations of soil type, advancing holes for other sampling methods, determining depth to 

top of bedrock, and installing wells. Auger borings can be made using posthole, helical, barrel, hollow

stem, or bucket augers. Auger samples are difficult to obtain below the groundwater table, except in 

clays. However, hollow-stem augers with continuous split barrel sampler can retrieve some soils from 

below the water table. 

Truck-mounted auger rigs currently come equipped with high yield and high tensile strength steel augers. 

New hydraulics technology can now apply torque upwards of 20,000 foot pounds. With this amount of 

torque, augers are capable of boring large size holes and of being used in soft bedrock foundation 

investigations. Because augers use no drilling fluids, they are advantageous for avoiding environmental 

impacts. 

Currently, many drilling rigs are actually a combination auger/core/downhole hammer unit. A hollow 

stem auger has the "drill through" capability, i.e. the auger can drill to refusal, then a wireline core barrel 

and drill rods can be inserted to finish the hole. Another advantage of using augers is the ability (using 

hollow stems) for soil sampling, i.e., taking samples below the bit. Hollow stem augers use a "plug" 

assembly that is either manually or mechanically set in the opening at the end of the auger string and then 

removed prior to sampling. Removal is commonly facilitated using a wire line system of retrieval. 

However, the soil below the bottom of the auger may become disturbed by the process of advancing the 

auger or by the removal of the plug at the bottom of the auger. The latter cause of disturbance is 

particularly serious for sandy soils below the water level. 

3.1.1.2 Drive Borings. Drive borings provide disturbed samples that contain all soil constituents, 

generally retain natural stratification, and can supply data on penetration resistance. Drive boring is a 

non-rotating, impact driven method for making a hole by continuous sampling utilizing a heavy wall 

drive barrel. Where larger samples are required, the most suitable drill for this method is the cable rig. 

The cable tool rig has the capability to provide a downward driving force (drill stem on drive clamps) to 

make a hole and an upward force (drilling jars) to remove the drive barrel from the hole. 

3.1.1.3 Wash Borings. A wash boring is advanced by a combination of water circulation and a 

loosening of the soils using various types of bits. The circulation of water (or other fluid) brings the soil 

cuttings to the surface. Water is injected from the bottom of the drilling rod assembly, with the water 

discharge being upwards to prevent disturbance below the bottom of the borehole. The borehole is kept 

open with a casing that is advanced separately, and/or with the use of a heavy bentonitic mud. When 

advancing boreholes below the water table, it is important to maintain the level of the fluid in the 

borehole above the water table to prevent the development of a quick condition at the bottom of the 

borehole. Wash boring is the preferred method of advancing a borehole for obtaining good quality 

samples or obtaining reliable measurements of penetration resistance (see Section IV).

31 NUREG/CR-5738
3. Borings and Exploratory Excavations

3.1.1.4 Rock Core Boring. Core drilling, if carefully executed and properly reported, can produce 

invaluable subsurface information. Basic procedures that should be followed and the information 

obtained can form the basis for comparison for widely diverse sites and conditions. The following 

subparagraphs outline procedures to report observations made during coring operations. 

3.1.1.4.1 Drilling observations. During the coring operation, a great deal of information is available 

about the subsurface conditions that may or may not be apparent in the core recovered from the hole. 

Observation of the drilling action must be made and reported to present as complete a picture, as 

possible, of the subsurface conditions. 

3.1.1.4.1.1 If coring with water as a circulating medium, the inspector should note the amount of water 

return relative to the amount being injected through the drill rods and its color. Careful observation of 

drill water return changes can indicate potential intervals where pressure test takes can be anticipated and 

correlated. Changes in the color of the return water can indicate stratigraphic changes and degrees of 

weathering such as clay-filled joints and cavity fillings. 

3.1.1.4.1.2 If available, hydraulic pressure being exerted by the drill should be recorded on each run as 

well as the fluid water pressure. While the drill is turning, the inspector should correlate drilling depths 

to drill action (e.g. smooth or rough), increases and decreases applied by the drill operator to the feed 

control valve, and the rate of penetration. Rod drop depths, which indicate open zones, should be 

recorded. Changes in drilling rates can be related to changes in composition and/or rock structure and, in 

areas of poor core recovery, may provide the only indication of the subsurface conditions. 

3.1.1.4.2 Procedural Information. Regardless of the program undertaken, all logs should at least 

include the following: size and type of core bit and barrel used; bit changes; size, type and depth of 

casing; casing shoe and/or casing bit used; problems or observations made during placement of the 

casing; change in depth of casing setting during drilling; depth, length, and time for each run; amount of 

core actually recovered; amount of core loss or gain; and amount of core left in the hole (tape check). 

From these data the unaccountable loss, i.e. the core that is missing and unaccounted for, should be 

computed. This loss should be shown on the graphic log at its most likely depth of occurrence based 

upon the drill action and close examination of the core. 

The "N" size hole (3.0 in., or 75 mm O.D.) is probably the core size most widely used by the Corps of 

Engineers for geotechnical investigations and produces a satisfactory sample for preliminary exploration 

work and, in many instances, for more advanced design studies. Other hole sizes, including B (2.5 in., or 

65 mm O.D.) and H (4.0 in., or 100 mm O.D.), are also quite satisfactory for geotechnical investigations. 

The decision on hole size should be based upon anticipated foundation conditions, laboratory testing 

requirements, and the engineering information desired. A double- or triple-tube core barrel is 

recommended because of its ability to recover soft or broken and fractured zones. 

Core recovery in zones of weak or intensely fractured rock is particularly important because these zones 

are typically the critical areas from the standpoint of foundation loading and stability. The use of larger 

diameter core barrels in soft, weak, or fractured strata can improve core recovery and does provide a 

statistically better size sample for laboratory testing. 

Although the majority of soil and rock core borings are drilled vertically, inclined and horizontally 

oriented borings may be required to adequately define stratification and jointing. Inclined borings should 

be used to investigate soils beneath existing structures or steeply inclined rock jointing in abutments and 

valley sections for dams, along spillway and tunnel alinement, and in foundations for other structures. In

NUREG/CR-5738 32
3. Borings and Exploratory Excavations

nearly vertical bedding, inclined borings can be used to reduce the total number of borings needed to 

obtain core samples of all strata. 

If precise geological structure is to be evaluated from core samples, techniques involving oriented cores 

are required. In these procedures, the core is scribed or engraved with a special drilling tool (Goodman, 

1976) so that its orientation is preserved. In this manner, both the dip and strike of any joint, bedding 

plane, or other planar discontinuity can be ascertained. A more common procedure for obtaining dip and 

strike of structural features is the use of borehole photography or television. If the orientation of bedding 

is consistent across the site, it can be used to orient cores from borings that are angled to this bedding. 

Once oriented, the attitudes of discontinuities can be measured directly from the core. 

3.1.2 Soil Identification and Description 

A thorough and accurate description of soils is important in establishing general engineering properties 

for design and anticipated behavior during construction. The description identifies the type of soil (clay, 

sand, etc.), places it within established groupings, and includes a general description of the condition of 

the material (soft, firm, loose, dense, dry, moist, etc.). Characterization of the soils within a site provides 

guidance for further subsurface exploration, selection of samples for detailed testing, and development of 

generalized subsurface profiles (Das, 1994). Initial field soil classification with subsequent lab tests and 

other boring data are recorded on the logs of borings. Soils should be described in accordance with 

ASTM D 2488, "Description of Soils (Visual-Manual Procedure)." The most widely used classification 

scheme is the Uniform Soil Classification System (USCS). The USCS outlines field procedures for 

determining plasticity, dilatancy, dry strength, particle size, and other engineering parameters. The 

USCS is described by TM No. 3-357 (DA, 1960), used all over the Corps, and by Schroeder (1984). 

Cernica (1993) provides detailed procedures to evaluate the physical properties of soils. In some cases a 

standardized description of color using Munsell charts is useful. Some of the procedures, such as 

determining dry strength, may be impractical under certain field conditions, and may be omitted where 

necessary. However, the checklists included in the procedure, if followed conscientiously, provide for a 

thorough description of soils. Examples for presenting soils data are shown in Appendix C. 

3.1.3 Rock Core Logging 

Each feature logged should be described in such a way that other persons looking at the core log will 

recognize what the feature is, the depth at which it occurred in the boring, and its thickness or size. 

Readers should also be able to obtain some idea of the appearance of the core and an indication of its 

physical characteristics. A complete photo log of recovered core is very helpful in recording core 

appearance. The log should contain all the information obtainable from the core pertaining to the rock as 

well as discontinuities. Examples for presenting core logging data are shown in Appendix C. 

Proper classification of subsurface materials can allow engineers to anticipate the soil or rock behavior 

during and after construction. The description of the site soils and rocks will be done first by visual 

inspection and simple field tests, and later corroborated in the laboratory. The engineering behavior of 

the sampled materials can be assessed by their index properties, obtained from established classification 

tests. 

Generally, the characteristics by which soils and rocks are described and classified include grain size, 

constituency, mineralogical composition, strength, degree of induration, plasticity, porosity, fractures, 

faults, deformations, and degree of weathering. Guidance in the description and engineering 

classification of intact rock and rock masses for USCE is available in EM 1110-1-2908 as an example.

33 NIUREG/CR-5738
3. Borings and Exploratory Excavations

3.1.3.1 Lithologic Description. Each lithologic unit in the core should be logged. The classification 

and description of each unit should be as complete as possible. A recommended order of descriptions is 

as follows: 

"* Unit designation (Miami oolite, Clayton formation, Chattanooga shale). 

"* Rock type and lithology. 

"* Hardness. 

"* Degree of weathering. 

"* Texture. 

"• Structure. 

"* Discontinuities (faults, fractures, joints, seams). 

"• Orientation with respect to core axis. 

"• Asperity (roughness). 

"• Nature of infilling or coating, if present. 

"• Staining, if present. 

"• Tightness. 

"* Color. 

"* Solution and void conditions. 

"• Swelling properties. 

"• Slaking properties. 

"* Additional descriptions such as mineralization, inclusions and fossils. 

Criteria for these descriptive elements are contained in Table 2. Murphy (1985) provides guidelines to 

geotechnical descriptions of rock and rock masses. Geological Society Engineering Group Working 

Party Report (1995) provides a description and classification scheme of weathered rocks for engineering 

purposes. TL 1110-2-282 outlines rock mass classification data requirements for rippability. 

Variation from the general description of the soils and features not included in the general description 

should be indicated at the depth and the interval in the soil sample sequence or rock core where the 

feature exists. These variations and features should be identified by terms that will adequately describe 

the feature or variation so as to delineate it from the general description. They include zones or seams of 

different color and texture; staining; shale seams, gypsum seams, chert nodules and calcite masses; 

mineralized zones; vuggy zones; joints; fractures; open and/or stained bedding planes, roughness, 

planarity; faults, shear zones, and gouge; cavities (thickness, open or filled, and nature of filling); and 

amount of core left in the bottom of the hole after the final pull. 

3.1.3.2 Rock Quality Designation. An easily done and widely used measure of the quality of the rock 

mass is provided by the Rock Quality Designation (RQD). This system, developed by Deere and Deere 

(1989) is a modified core recovery percentage which incorporates only intact pieces 4 inches or longer. 

In practice the RQD is measured for each core run and reported on an appropriate form for record. Many 

of the rock mass classification systems in use today are based, in part, on the RQD. Its wide usage and 

ease of measurement make it an important piece of information to be gathered on all core holes. It is also 

desirable because it is a quantitative measure of core quality at the time of drilling before handling and 

slaking have had any effect. Special attention should be paid to the nature of all discontinuities. These 

are most often what control the engineering behavior of the foundation rock mass and slope stability. 

3.1.3.3 Solution and Void Conditions. Solution and void conditions should be described in detail 

because these features can affect the strength of the rock and can indicate potential groundwater seepage 

paths. Where cavities are detected by drill action, the depth to top and bottom of the cavity should be

NUREG/CR-5738 34
3. Borings and Exploratory Excavations

determined by measuring. Filling material, where present and recovered, should be described in detail 

opposite the cavity location on the log. If no material is recovered from the cavity, the inspector should 

note the probable conditions of the cavity, as determined by observing the drilling action and the color of 

the drill fluid. If drill action indicates material is present, i.e., slow rod drop, no loss of drill water, or 

noticeable change in color of water return, it should be noted on the log that the cavity was probably 

filled and the materials should be described as well as possible from the cuttings or traces left on the 

core. If drill action indicates the cavity was open, i.e., no resistance to the drill tools and/or loss of drill 

fluid, this should be noted on the drill log. By the same criteria, partially filled cavities should be noted. 

If possible, filling material should be sampled and preserved. During the field logging of the core at the 

drill site, spacers (ER 1110-1-1802) should be placed in the proper position in core boxes to record voids 

and losses. 

3.1.3.4 Rock Joint Description. Detailed descriptions of joint orientation, degree of fracturing, joint 

wall weathering and separation, and frequency in the rock mass or core, are necessary and useful for 

assessing sliding stability, bearing capacity, and deformation/settlement. Strike and dip angles of 

discontinuities. as well as thickness, and joint aperture should be recorded. 

3.1.3.5 Photographic and Video Record. A color photographic record of all core samples should be 

made. Digital color photographs should be taken as soon as possible after retrieving the core samples. 

Photographs often enhance the logged description of cores particularly where rock defects are abundant. 

In the event that cores are lost or destroyed, the photographic record becomes the only direct, visual 

means for revieA of subsurface conditions without expensive redrilling. 

A video recording of the drilling operation provides an excellent record of drilling equipment and 

procedures Moreover, video may provide a record of critical events or conditions that were not obvious 

at the time. or occurred too quickly to be recorded manually. 

3.2 Borehole Examination 

3.2.1 Visual Records 

3.2.1.1 Borehole Photography. The interpretation of subsurface conditions solely by observation, 

study, and testing of rock samples recovered from core borings often imposes an unnecessary limitation 

in obtaining the best possible picture of the site subsurface geology. The sidewalls of the borehole from 

which the core has been extracted offer a unique picture of the subsurface where all structural features of 

the rock formation are still in their original position. This view of the rock can be important, particularly 

if portions of rock core have been lost during the drilling operation and if the true dip and strike of the 

structural features are required. Borehole viewing and photography equipment includes borescopes, 

photographic cameras, TV cameras, sonic imagery loggers, caliper loggers, and alignment survey 

devices. 

3.2.1.2 Borehole Camera and Borescope. Borehole cameras that have limited focus capability are 

satisfactory for examining bedrock features on the sidewalls of the borehole. However, the small 

viewing area and limited focus reduce their usefulness in borings that have caved or have cavities. They 

are best used for examining soft zones for which cores may not have been recovered in drilling and for 

determination of the dip and strike of important structural features of the rock formation. Borescopes 

have limited use because of their small viewing area, limited depth, and cumbersome operation. They are 

relatively inexpensive to use.

35 NUREG/CR-5738
3. Borings and Exploratory Excavations

3.2.1.3 Borehole Video Camera and Sonic Imagery. The TV camera has variable focus and is suitable 

for examining the nature and approximate dimensions of caving sections of open boreholes or boreholes 

filled with clear water. The sonic imagery (televiewer) system uses acoustic pulses to produce a borehole 

wall image and can be used in a hole filled with drilling mud. The TV camera is used to examine cavities 

in the rock such as solution voids in calcareous formations, open cooling joints and lava tunnels in 

volcanic rocks and mines, tunnels, and shafts. The televiewer can be used to distinguish fractures, soft 

seams, cavities, and other discontinuities. Changes in lithology and porosity may also be distinguished. 

Specially designed borehole television cameras and sonic images or televiewers can be used to determine 

the strike and dip of discontinuities in the borehole wall. 

3.2.2 Alignment Surveys 

Precise determination of travel distance is required for proper interpretation of results from geophysical 

tests (presented in a later section) between two boreholes. Alignment, or deviation, surveys are required 

to account for plumb and/or orientation of a borehole if subsequent geophysical surveys are to be 

performed. Older methods employed a compass and photograph system which was relatively easy to use. 

More modem systems are electronic. Alignment surveys are particularly necessary in deep holes, and 

where instrumentation packages are to be installed, or where precise determinations of structural features 

in the rock formation are required. Borehole deviation survey services are available from commercial 

logging or drilling firms. 

3.3 Exploratory Excavations 

3.3.1 Test Pits, Shafts, and Trenches 

Test pits and trenches can be constructed quickly and economically by bulldozers, backhoes, pans, 

draglines, or ditching machines. Depths generally are less than 20 to 30 feet, and sides may require 

shoring if personnel must work in the excavations. Test pits, however, that are hand dug with pneumatic 

jackhammers and shored with steel cribbing can be dug to depths exceeding 60 feet. Test pits and 

trenches generally are used only above the water table. Test pits that extend below the water table can be 

kept open with air or electric powered dewatering pumps. Test shafts may be excavated using large 

augers or other caisson drilling equipment; these shafts are maintained open using steel casing and can 

extend deeper than 60 feet. Dewatering from inside the excavation may prove practical in a cased shaft 

until inflow either exceeds the capacity of the pumping equipment or uplift seepage pressures disturb the 

sampling surface at the bottom of the shaft. Otherwise a dewatering system must be installed outside the 

cased excavation capable of maintaining the water level below the maximum depth of the intended shaft 

exploration. One or more of these excavations may be desired to permit access to in situ soils for 

in-place density determination and high-quality sampling. 

Exploratory trench excavations are often used in fault evaluation studies. An extension of a bedrock 

fault into much younger overburden materials exposed by trenching is usually considered proof of recent 

fault activity. Shallow test pits are commonly used for evaluating potential borrow areas, determine the 

geomorphic history, and assessing cultural resource potential. 

3.3.2 Calyx Hole Method 

Large diameter calyx holes have been used successfully on some jobs to provide access for direct 

observation of critical features in the foundations. These holes are very expensive to drill so their use is

NUREG/CR-5738 36
4. Sampling Methods

very limited. However, where in-situ observation of a very sensitive feature, such as a shear zone or 

solution feature in the abutment of an arch dam, can not be achieved reasonably by any other means, the 

calyx hole may be the procedure of choice. The method involves circulation of a sludge of steel shot that 

aids in the abrasion of rock at the leading edge of an internal, coring bit (Krynine and Judd, 1957). 

4 SAMPLING METHODS 

The depth, layout, spacing of sampling borings, and sampling requirements for a site study depends on 

the subsurface requirements of the foundation, which are a function of the intended use of the site, and 

the complexity of the subsurface. Complex areas with evidence of adverse anomalies or discontinuities 

will require supplementary borings or soundings which would be distributed according to the features 

found and at a spacing small enough to detect them. Subsurface investigation methods for favorable or 

uniform typical geologic conditions are tabulated in Appendix D. Guidelines for spacing and depth of 

borings for safety-related structures are included in Appendix E. 

The number of samples required to adequately characterize the engineering features of a foundation site 

will depend on the complexity of the study area. Where the geology of the area is known to be relatively 

uniform, a lower frequency of sampling will suffice. In more complex areas, further sampling will be 

needed to guarantee an adequate and representative coverage. The variation, size, and periodicity of 

features that need to be detected in a complex study site must be considered to design and customize the 

sampling plan. Probabilistic considerations for drilling explorations are presented as an option for the 

correct sampling coverage of a complex site (Franklin et al., 1981), using geometric probability and 

search theory. Exploration grids can be used when there is no available information on the deposition 

and location, size, or periodicity of target features, to assure uniform coverage. 

4.1 Techniques for Recovery of Undisturbed Samples 

Borings for undisturbed sampling of soils - It is physically impossible to obtain truly "undisturbed" 

samples because of the adverse effects resulting from the sampling process itself (e.g., unloading due to 

removal from confinement), shipping, or handling. However, modem samplers, used with great care, can 

obtain samples that are satisfactory for shear strength, consolidation, permeability, and density tests, 

provided careful measurements are made to document volume changes that occur during each step in the 

sampling process. Undisturbed samples can be sliced to permit detailed study of subsoil stratification, 

joints, fissures, failure planes, and other details. Undisturbed samples of clays and silts can be obtained 

as well as nearly undisturbed samples of some sands. 

There are no standard or generally accepted methods for undisturbed sampling of cohesionless soils. 

Care is necessary in transporting any undisturbed sample; sands and silts are particularly vulnerable to 

vibration disturbance. One method to prevent handling disturbance is to obtain 3-inches. Shelby tube 

samples, drain them, and then freeze them prior to transporting them to the laboratory. Another method 

used consists of in-situ freezing, followed by sampling with a rotary core barrel. For both methods, 

disturbance by cryogenic effects must be taken into account. Singh, Seed, and Chan (1982) examined in 

situ freezing techniques for undisturbed sampling of saturated sands. They found that strength behavior 

of clean sands was essentially unaltered by freezing, either in situ or once sampled in thin-walled tubes 

removed from the ground, as long as free water was allowed to drain out the sample ahead of the freezing 

front. Tani and Yasunaka (1988) studied the effects of in situ freezing to sample sands with up to

37 NUREG/CR-5738
4. Sampling Methods

6 percent particles finer than 74 micrometers (i.e., passing the U.S. Standard No. 200 sieve). Their 

results indicated that there was no change in cyclic triaxial laboratory strengths for alternately frozen and 

thawed specimens. The authors claimed that cyclic strengths measured in samples taken by in situ 

freezing were thus representative of "true liquefaction resistance." Soils with higher fines contents, 

particularly low-plasticity silty or clayey soils, may be highly susceptible to frost heave (e.g., Lambe and 

Whitman, 1969), thus in situ freezing may be inadvisable in fine-grained soils. 

So-called "undisturbed" samples are normally obtained using one of two general methods: push samplers 

or rotary samplers. Push sampling types involve pushing a thin walled tube using the hydraulic system of 

the drill rig then enlarging the diameter of the sampled interval by some "clean out" method before 

beginning to sample again. Commonly used systems for push samples include the Hvorslev fixed

position sampler and the Osterberg hydraulic piston sampler. Rotary samplers are considered slightly 

more disruptive to soil structure and involve a double tube arrangement similar to a rock coring operation 

except that the inner barrel shoe is adjustable and generally extends beyond the front of the rotating outer 

bit. This reduces the disturbance caused to the sample from the drill fluid and bit rotation. Commonly 

used rotational samplers include the Denison barrel and the Pitcher Sampler. 

4.1.1 Hand Trimming of Block Samples 

Test pits and shafts offer the only effective access to collect high quality block samples and to obtain 

very detailed information on stratification, discontinuities, or preexisting shear surfaces in the ground. 

Cost increases with depth as the need of side wall support arises. Samples can be obtained by means of 

hand-carving oversized blocks of soil or hand-advancing of thin-walled tubes as performed using the GEI 

sampler (GEI Consultants, Winchester, MA) or other, similar device. The GEI tripod sampler is used to 

maintain a 3-inch diameter, 14-inch long, thin wall sampling tube in vertical alignment. The tube is 

advanced in increments of about 1/2 inch by using no more than light hand pressure. About 1/2 to 1 inch 

of soil around the periphery of the tube, below the cutting edge, is excavated prior to advancement of the 

tube. This pre-excavation allows soil to easily peel away from the tube as it is advanced and minimizes 

volume changes during sampling. Several hours of effort are required to obtain each sample. Detailed 

measurements of tube penetration and soil recovery are made during advancement of the tube. These 

measurements allow control and documentation of any volume changes that might occur during 

sampling. An example of the use of this sampler is described by Castro, Keller, and Boynton (1989). 

4.1.2 Thin-wall Tube Samplers 

Two early versions of samplers continuously pushed to recover high quality samples are shown in 

Figure 4. Check valves prevent washout of soil within the tubes on removal from the boring. Samples 

are extruded mechanically, or the tubes may be sawed in half. The tubes are advanced either by direct 

pushing (without rotation), or by means of a rotary core-barrel apparatus. Rotary core-barrel samplers 

include the Denison sampler and are best suited to sampling in stiff soils that would preclude smooth 

penetration of direct push devices, or soils which contain appreciable gravel particles. 

4.1.3 Fixed-piston-type Thin-wall Tube Samplers 

Two types of fixed-piston sampler are generally deployed to obtain high-quality samples in clays, silts 

and sands without boulders or gravel-sized particles: mechanically activated (e.g., the Hvorslev fixed

piston sampler, Figure 5, and the Butters sampler, which is a simplified version of the Hvorslev device); 

and hydraulically or pneumatically activated (e.g., the Osterberg sampler or similar devices). Detailed 

directions on assemblage and sampler operation for both types of fixed-piston devices can be found in

NUREG/CR-5738 38
4. Sampling Methods

- Casing 

- Vents 

- Drill rod 

- SpeciaJ coupling 

or plug 

_ 9mm Allen 

set screws 

52mm Shelby 

steel tubing 

16 to 18ga. 

(1.63 to 1.22mm)

Figure 4. Early thin-walled open-drive samplers, Hvorslev 1940. (Clayton, Matthews, and Simons, 

1995; reprinted with permission)

NUREG/CR- 5738

E 

E 

E 

E 

C'j 

co N*

E 

E 

E 

E 

E 

E 

CO

39
4. Sampling Methods

Piston rod

Piston rod screw clamp left hand 

thread

Exit port 

Allen set screws 

Vacuum release 

screw 

Rubber sealing 

ring

- Hollow outer 

drill rods 

- Spring loaded 

cone clamp 

Thin walled 

sample tube 

Rolled and 

reamed edge 

Piston

Figure 5. Hvorslev fixed-piston thin-walled tube sampler (Clayton, Matthews, and Simons, 1995; 

reprinted with permission).

NUREG/CR-5738 40
4. Sampling Methods

EM 1110-1-1906 (DA, 1996). When fixity of the piston upon advancing the tube is important, the piston 

rods should be secured to a fixed frame attached to the ground or the boring casing, but not to the drilling 

rig. The drilling rig is the reaction for pushing the tube down, and thus it will move upwards as the tube 

is pushed. Practitioners have encountered problems maintaining fixity of the piston activation rods in 

holes at depths greater than about 150 feet, due to flexibility inherent in rod strings of that length. 

Hydraulically activated piston samplers can be modified so that the length of the push and the subsequent 

locking of the piston are accurately controlled to a predetermined value (Dr. Gonzalo Castro, GEI 

Consultants, Winchester, MA, personal communication). 

4.1.4 Foil and Stockinette Samplers 

These samplers were developed to obtain long, continuous samples in soft, cohesive soils, and are pushed 

with a fixed-piston operation. In each, as the sampler is pushed (not requiring a borehole), the internal 

piston retracts and a sliding liner (either an impervious metallic foil or a woven stocking) is unrolled 

from a storage magazine in the sampler head to surround the sample within the sampling tube as the drive 

progresses. Specific design and operational aspects of each device are detailed in EM 1110-1-1906 (DA, 

1996). 

4.1.5 Large-diameter Laval Sampler 

The large-diameter Laval sampler is not commonly used within the U.S. It was originally designed for 

sampling soft, sensitive marine clays (La Rochelle et al., 1981) and has been successfully used to sample 

saturated cohesionless soil deposits like fine-grained saturated sands (Konrad et al., 1995). This 

technique for fine-grained saturated sands is a less expensive alternative to in situ freezing and more 

efficient than thin-walled tubes for undisturbed sampling. Thin-wailed tubes have a tendency to loosen 

dense sands and densify loose soils due to the small ratio of wall thickness to the diameter of sampling 

tube (Baligh, 1985). The large-diameter Laval sampler dimensions help to minimize the mechanical 

disturbance of the samples since the ratio effect has been taken into account. The Laval sampler has 

produced high quality undisturbed samples of sensitive clays that proved to be equivalent to block 

samples (La Rochelle et al., 1981). 

The Laval sampler consists of a sampling tube fixed to a sampler head inside an overcoring tube 

(Figure 6) (Konrad et al., 1995). The sampling head has an opening in the center that allows the mud to 

flow from the sampling tube to the overcoring tube as it is pushed into the ground. The hole can be 

closed from the surface with a central rod avoiding the flow of mud into the sampler head as the sampler 

is removed. Details on the Laval sampler drilling equipment and sampling procedures can be found in 

Konrad et al., 1995 and La Rochelle et al., 1981. The sample is carefully retrieved to the surface, 

avoiding any kind of tilting to preserve sand structure. Once the sample is on the surface, unidirectional 

freezing in open system conditions is used to preserve and solidify the sample for transportation 

(Figure 7) ( Konrad et al., 1995). 

4.2 In Situ Soil Testing 

The standard penetration test (Figure 9) is a soil index test used to obtain the resistance to penetration by 

counting the number of blows required to drive a steel tube of specific dimensions into the subsoil a 

specified distance using a hammer of a specified weight (EM 1110-1-1906, DA, 1996). The Standard 

Penetration Test (SPT) method of drive boring, described in ASTM D 1586, is probably the most 

commonly used method for advancing a hole by the drive method. Slight variations exist with this 

method, primarily concerning the sampling interval, clean out method, and the refusal criteria, but the

41 NUREG/CR-5738
4. Sampling Methods

The Laval 200mm diameter tube sampler (La Rochelle, Sarrailh, Tavenas, Roy 

and Leroucil 1981).

Figure 6. The Laval tube sampler (Clayton, Matthews, and Simons, 1995; reprinted with permission).

NUREG/CR-5738 42
4. Sampling Methods

Figure 7. General operation of the Laval sampler (Clayton, Matthews, and Simons, 1995; reprinted with 

permission).

NUREG/CR-573 8

(a) (b)~ (d) d

I

43
4. Sampling Methods

SE 050mm 

? [

CLE 

E 

IN

00 

C, E 

t E 

.2 E 

TE -16mm 

o35mm

65kg free drop trip 

hammer ('Monkey)

Striker plate 

Connector to 

32mm rods 

Round A rods 

or square 32mm 

boring rods 

Split spoon 

Standard 

cutting shoe 

60o cone for gravel.

Figure 8. Standard Penetration Test equipment (Clayton, Matthews, and Simons, 1995; reprinted with 

permission). 

NUR.EG/CR-5738 44

!
4. Sampling Methods

fundamental procedure follows the ASTM standard. In this method a standard configuration 2-inch-OD 

split barrel sampler at the end of a solid string of drill rods is advanced for a 1.5-foot interval using a 

140-pound hammer (the safety hammer used in the U.S. is not shown in Figure 8) dropped through a 

30-inch free fall. The blows required to advance the hole for each 6-inch interval are recorded. The hole 

is then cleaned out or reamed to the top of the next interval to be sampled and the procedure is repeated. 

Refusal is generally defined as 50 blows per half foot of penetration. When used to define the top of 

rock, great care and close examination of samples are required to minimize uncertainties. This impact 

method may also be used with larger sample tubes and heavier hammers. Correlation studies to 

normalize data from larger holes to the SPT have been performed but are not completely reliable. The 

SPT can be used in relatively clean medium-to-coarse sands and fine gravels with a variable amount of 

moisture, and in saturated or nearly saturated cohesive soils. Non-saturated cohesive soils and saturated 

silty sands can produce misleading N-values (the standard penetration resistance, or number of blows 

required to penetrate the final 12 inches of an 18-inch drive). Typical SPT testing and sampling intervals 

are of 0.6 to 1.5 m (2 to 5 feet) in uniform strata and whenever there is a change of strata. Control of the 

hammer drop can be by manual, automatic, semiautomatic, or trip-hammer drop systems. 

Borehole disturbance can affect SPT results dramatically, and may reduce N values to a fraction of the 

value that would be obtained in undisturbed ground. SPT blow count data can also be affected by the 

penetration interval, the sampling tube design, the number of turns of rope on the cathead winch used to 

raise the safety hammer between blows, variations on drop height, energy delivered to the sample tube, 

or split-spoon, in situ stress conditions, faulty equipment, and overboring. The suggested approach is to 

follow standard procedures, to be aware of the potential errors and error sources that can affect the 

technique, and take errors into account when collecting and interpreting SPT data. EM 1110-1-1906 

(DA, 1996) describes the STP method and suggests modifications to the interpretation procedure. 

The N-value has been empirically correlated with liquefaction susceptibility under seismic loadings 

(Seed, 1979). The use of SPT data in correlations developed for liquefaction potential assessment 

requires detailed documentation of field procedures. Energy measurements have been made to permit 

comparison of data obtained using different hammers, rigs, and operators, accounting for blow count 

variation due to these factors. For safety-related structures where earthquake effects need to be 

considered, it is recommended that driving energy be determined and recorded sufficiently often to 

calibrate the equipment used at a specific site. The N-value is also useful for pile design. In cohesive 

soils, the N-value can be used to determine where undisturbed samples should be obtained. The N-value 

can also be used to estimate the bearing capacity (Meyerhof, 1956; Parry, 1977) and the unconfined 

compressive strength (Mitchell, Guzikowski, and Villet, 1978) of soils. The split-spoon sampler driven 

during an SPT recovers disturbed soil that may be used for visual classification and laboratory index 

testing, including determination of natural water content. Longer samplers are commercially available 

for recovery of coarse-grained soils. 

4.3 Alternative Sampling Techniques 

4.3.1 Hand sampling 

Hand sampling in test pits, shafts, or other accessible excavations may be required to produce 

representative samples in boulders, gravels, or sand-gravel mixtures.

45 NUREG/CR-5738
4. Sampling Methods

4.3.2 Freezing Sampling 

In situ freezing followed by coring of frozen soil is an alternative technique to collect undisturbed 

samples of cohesionless materials like loose sands and gravelly soils. In situ freezing can be used to 

stabilize the soil before sampling or after sampling to avoid further disturbance of the sample. The 

quality of the samples obtained by this method will depend on the amount of density and soil structure 

changes the freezing and the sampling technique may provoke in the sample. The recommended freezing 

technique for high quality undisturbed samples consists of one-dimensional ground freezing followed by 

core sampling (Singh, Seed, and Chan, 1982). Relatively clean sands or gravels with good drainage are 

good materials to sample by freezing (Figure 8) since the freezing process can be performed and 

maintained one-dimensionally. Their inherently good drainage allows the freezing front to expand out 

through the ground without major alteration of the volume or soil structure as the water freezes. In situ 

freezing will be inhibited at sites with high groundwater gradient, as warmer groundwater flowing 

through the target zone may prevent the recirculating coolant from maintaining freezing temperatures in 

the soil to be sampled. The amount and nature of fine material present in the ground will also 

dramatically affect the applicability of freezing as a source of undisturbed samples. The presence of 

fines may inhibit the free drainage of the excess water created by the expansion of water into ice, thus 

causing void expansion and possibly ice lenses that will severely damage the structure of the soil. It may 

be necessary in the laboratory to observe a thaw protocol, such as providing confinement pressure near 

the in situ level during warm-up of the specimen in a test cell, to preserve original structure and strength 

behavior in frozen soils (Dr. Dave Sego, University of Alberta, personal communication). 

4.3.3 Chemical Stabilization or Impregnation 

Chemical stabilization or impregnation can be used to obtain samples for density determination from 

boreholes. Chemical impregnation provides an option to sample and preserve the natural structure of 

cohesionless granular material that would be hard to sample without disturbance, if at all. Agar has been 

used as an impregnation material for undisturbed sampling of sands below the water table as an 

alternative to freezing with positive results. The characteristics of the agar make its use simple, 

inexpensive, and free of contamination potential. The material is easy to handle and does not seem to 

appreciably change the soil's natural characteristics. 

Chemical impregnation can be used either after sampling, to avoid further disturbance in transportation 

and handling of the samples, or by in situ impregnation before sampling. Both ways represent an 

alternative to freezing that is less expensive and produce samples that are easier to manage after 

collection. Removal of the impregnating material maybe accomplished once the sample is in the 

laboratory. 

4.4 In Situ Sampling for Specific Site Conditions 

4.4.1. Cohesive and Plastic Soils 

Cohesive and plastic soils are relatively easier to study and sample than cohesionless soils, with a variety 

of techniques. These soils include all soils with some degree of cohesion and plasticity, from clayey, fine 

sand and silt, to plastic clays and firm peat. Depending on the soil consistency, several methods of 

boring and sampling can be used to obtain suitable results.

NUREG/CR-5738 46
4. Sampling Methods

Figure 9. Method of sand sampling by freezing probe (after Yoshimi, Hatanaka, and Oh-Oka, 1977).

NUREG/CR-5738

Freezing tube

Cement plug

47
4. Sampling Methods

Uncased and dry bore holes are usually sufficient for sampling at shallow depths (less than 20 feet). 

Deeper boreholes should be stabilized with casing or drilling fluid to prevent caving when sampling. 

Open drive samplers can be used to obtain undisturbed samples, but thin-walled samplers of large 

diameter used with a stationary piston produce the longest, least disturbed samples. Core boring 

procedures can be used on stiffer soils. Advance trimming or box sampling are recommended for stiff 

and brittle soils. Since cohesive and plastic soils vary widely in their physical properties, the maximum 

depth of penetration and the diameter of the sampler will depend on the soil character. In general, 

sample loss is not as common when the sample diameter is less than 3 inches, but when retrieving larger 

samples a snare wire should be used to cut samples from the subsoil. 

4.4.2 Slightly Cohesive and Brittle Soils 

The soils included in this category include silt and fine sand with small amounts of clay or other 

cementation, such as loess, and partially saturated silt and loose sand with some apparent cohesion. 

Since these soils are easily disturbed, borings in partially saturated soils should be kept dry or if 

necessary filled with viscous drilling fluid instead of water. Casing, when used, should be advanced 

without vibrations and never ahead of the core. Generally, good samples can be obtained using open 

drive samplers or piston samplers. The sampling tubes should have very thin walls to avoid disturbance 

or displacement of the soil. Samplers with a stationary piston will produce the longest, least disturbed 

samples, with less risk of losing the sample. Even though core sampling can be used satisfactorily in 

these kinds of soils (e.g., using the Denison core barrel sampler), it is not clear that the vibrating 

disturbance of thus produced is not greater than the soil displacement disturbance produced by a thin

walled sampler. 

4.4.3 Very Soft Soils 

The soils included in this category include soft clays, soft peat, organic silt, and various mixtures of these 

soils or fine sand with decayed organic matter. These soils are often found in rivers, estuaries, tidal flats, 

and harbors and are commonly called mud or ooze. 

Casing and drilling fluid are necessary to avoid caving of the boreholes when sampling these soils. 

Friction and adhesion develop quickly producing lateral deformation and internal friction that can be so 

high that the soil under the sampler is pushed aside instead of entering the tube. To avoid this, the 

pressure over the sample has to be reduced, or the friction and adhesion development prevented by a high 

speed of penetration. 

Good quality samples are difficult to obtain in very soft or sensitive clays. The best procedure to obtain 

soft soil samples involves a piston sampler with stationary piston, as described earlier. This technique 

allows for consistent recovery of samples 2 inches in diameter and a length of 3 to 4 feet, even in 

extremely soft and sticky soils (longer samples are possible with the foil or stockinette samplers 

described in a previous section). Samples larger than 3 inches diameter are harder to recover even with 

increased pressure below the sample unless core retainers are used. Shallow surface samples can be 

obtained with short, thin-walled drive samplers of either open or stationary piston type. To sample at 

greater depth, stress changes and plastic deformations can be minimized by sampling from boreholes kept 

filled with water or drilling mud.

NUREG/CR-5738 48
4. Sampling Methods

4.4.4 Saturated Silt and Loose Sand 

The soils in this category include inorganic silt and loose to medium dense sand when found below 

groundwater level. 

Casing and drilling mud or fluid are necessary to avoid caving of the boreholes when sampling these 

soils. When undisturbed samples are the goal, the casing should be advanced by rotation, and jacking. 

Vibrations should be avoided since the internal structure and the void ratio of these soils can be easily 

disturbed. The casing may be kept 1 to 2 feet above the bottom of the borehole prior to sampling, to 

minimize disturbance of the soil to be sampled caused by casing advancement. The bottom of the 

borehole must be carefully cleaned with special tools to remove cuttings and other disturbed materials. A 

firm clean bottom is essential for good quality sampling. 

The preferred method to advance the borehole for sampling of saturated silts and sands is by washing 

techniques, with a bentonitic mud as drilling fluid. Truly undisturbed sampling of these materials in their 

in situ condition is not possible. Some volume changes are unavoidable. It is thus important for the 

sampling procedure to allow for the measurement of the volume changes so that the quality of the sample 

can be assessed and for making corrections to the soil properties measured in the samples. A fixed piston 

sampler has been successfully used for this purpose (Castro, Keller, and Boynton, 1989). 

The tube sampling procedure consists of lowering the sampler to the bottom of the borehole with the 

actuating rods (attached to the fixed piston) inside the drill rods. The actuating rods are then fixed to an 

independent frame that is set up over the borehole. The frame can be supported on steel rods driven into 

the ground. The sampler is pushed hydraulically in a smooth continuous motion until a maximum 

allowable pressure or 24 inches of penetration is reached. Trial sampling is needed to select the 

maximum hydraulic pressure that can be used without deforming the cutting edge. Short samples are 

acceptable for measuring void ratio and laboratory testing. The penetration and any movements of the 

actuating rods and frame are carefully measured before and after each push. The tube is withdrawn from 

the bottom of the borehole in a smooth constant motion using hydraulic pressure to pull the tube at a rate 

of 1 inch per second or less for the first 2 feet. After the sampler is pulled free from the bottom of the 

borehole, withdrawal continues to the ground surface at a slow uniform rate no greater than 1 foot per 

second. 

Special care must be taken to avoid jarring or disturbing the tube samples during sampling, storage, and 

transportation. Each tube must be held in a vertical position at all times from sampling in the field to 

arrival at the laboratory. Precise measurements are made of sample penetration, sample recovery length, 

and any change in sample length during storage and transportation. 

The clearance ratio of the cutting edge of the sampling tube should be adjusted for the particular sand so 

that the clearance ratio (CR) has the minimum value necessary to retain samples. Typically, values of 

CR of about 0.5 percent work for most sands. 

For sample diameters up to 3 inches, injection of compressed air under the sample or advance and 

cleaning before withdrawal may sometimes prevent loss of sample. Freezing the lower part of the sample 

before withdrawal has been proposed as a way of preventing sample loss in these kinds of soils. To 

retrieve undisturbed samples of these extremely loose soils, increasing the pore water viscosity by 

cooling it without actual freezing before sampling has been suggested. When undisturbed sampling is 

performed in test pits or other accessible excavation, the samples should be under capillary pressure so 

they acquire some apparent cohesion. This condition is attained by lowering the groundwater level

49 NUREG/CR-5738
4. Sampling Methods

below the bottom of the samples to be taken. Depending on the attained density of the soil, a thin-walled 

drive sampler or advance trimming may be used to take the samples. Careful field handling and 

transportation of these samples from the field to the laboratory are critical to avoid shock and vibrations, 

and preserve sample quality. 

4.4.5 Compact or Stiff and Brittle Soils 

The soils in this category include very dense sand; very stiff and brittle clays, and clayey, silty, and sandy 

soils that have been strongly compacted or have acquired considerable cohesion due to partial drying. 

Bore hole stabilization with drilling fluid or mud is appropriate and casing can be used if required. Only 

viscous drilling fluid should be used, never clear water. When undisturbed samples of partially saturated 

soils or dried soils are to be taken, the bore hole should be kept as dry as possible. Open drive samplers 

and piston samplers can be used to obtain samples, but hammering or large pressures may be needed to 

thrust the sampler into the soil, especially when dense deep sands are present. Permeable and partially 

saturated soils may be compacted by this action and brittle soil samples can show shear failure 

disturbance. Core boring may provide less disturbed samples when the soil is relatively impervious and 

viscous drilling fluid and/or foam is used. Auger core barrels are used in dry bore holes to avoid drilling 

fluid contamination of permeable, partially saturated or dry soil samples. Cohesive soils can be retrieved 

easily but sand samples require the use of core retainers to prevent loss, especially in loose sand or silt. 

Advance trimming, box sampling or auger core boring should be used when obtaining undisturbed 

samples in test pits or other accessible excavations. Thin-walled drive samplers can be used to determine 

the natural density of the soil but not accurately when the soil is permeable or not fully saturated. 

4.4.6 Hard and Partially Cemented Soils 

This categor) includes hard and brittle clays, partially cemented soils, such as marl and hardpan, and 

highly compacted glacial till without significant amounts of gravel and stones. 

Rotary or percussion drilling are generally necessary to advance a borehole in this material. Drilling 

fluid may be used to avoid gradual squeezing of deep bore holes. Drive samplers with thick walls can be 

hammered into these soils to obtain disturbed samples but the maximum penetration depth is usually 

small. Core boring will provide longer, less disturbed samples and, when sampling in accessible areas, 

box sampling methods are recommended. 

4.4.7 Gravelly Soils 

Representative samples of coarse-grained soils that include sands, gravels, and mixed soils can be 

extremely difficult to sample for laboratory analysis. Some may be impossible to sample since the 

sampler and the soils can both be destroyed or the soils completely disturbed by sampling operations. 

For these kinds of soils, in situ geophysical techniques and dynamic penetration techniques are potential 

alternatives. The Becker hammer drilling technique is specifically designed to provide a highly disturbed 

sample of coarse grained materials. The Becker hammer drill, marketed by the Layne Christensen 

Company of Mission Woods, Kansas, is a reverse circulation hammer drill that uses air and a double

walled drill casing to bring cuttings to a cyclone separator at the ground surface. The casing is driven 

using a double acting diesel pile driver and a toothed cutting bit. Driven with a plugged bit, the Becker 

hammer drill accommodates a penetration test to determine in situ strength in large-particled soils. The 

penetration test is discussed in a later section.

NUREG/CR-5738 50
4. Sampling Methods

Undisturbed samples of these materials may be obtained by freezing the soil beneath the bottom of the 

borehole and then core boring. Techniques are also being developed whereby a larger volume of gravelly 

soil is frozen using a single probe and the resulting column or bulb of soil is removed, with the probe 

inside, to the ground surface for subsampling. 

4.4.8 Tills 

Gravel deposits and soils containing considerable amount of gravel and stones like glacial till are 

included in this category. 

In these soils bore hole advance is slow and difficult, wash boring cannot be used and rotary drilling is 

inefficient. Borings may be advanced by displacement boring or with augers in loose gravelly soils. 

Compact deposits may be loosened with precision drilling and removed with bailers, sand pumps, or 

barrel augers. In stony soils, heavy-walled drive samplers are driven into the soil by a drop hammer, 

often damaging the cutting edge. Core boring cannot be used to sample loose gravel but it is an 

alternative for compacted or stony soils with some cohesive material. In both techniques the sample can 

be significantly disturbed since larger rocks get pushed either aside or into the sample. The Becker 

hammer drill, driven with open casing, is a good technique to obtain disturbed samples of coarse gravels; 

representative samples of clean gravels may also be obtained with barrel augers. 

As is the case with gravelly soils, undisturbed samples of these materials may also be obtained by 

freezing the soil beneath the bottom of the borehole and then core boring. 

4.4.9 Materials Unsuitable for Construction 

Unsuitable materials generally need to be removed, wasted or greatly modified for construction due to 

undesirable characteristics. Some materials unsuitable for construction are: organic soil, peat, collapsible 

soils, clays with high swell and shrinkage potential, and sensitive or soft clays. Loess can be unsuitable 

for construction under certain conditions, but it has been used successfully as construction fill when 

properly remolded (Krinitzsky and Turnbull, 1967). Unsuitable soils become undesirable because of 

their low strength, low compressibility, low permeability, stickiness in construction, etc. These kinds of 

materials should be identified in the field, sampled, and tested, to establish their vertical and lateral 

extent and the specific characteristics of the material. The boundaries of unsuitable material should be 

determined with the appropriate accuracy and precision. 

4.4.10 Collapsible Soils 

Collapsible soils are those that suffer a sudden volume reduction when they become saturated and load is 

applied. Their soil structure is characterized by high porosity and low density. This includes soils 

composed of silt, fine sand-size particles and smectite (clay soils that can hold a quantity of water greater 

that the liquid limit). An in situ technique using a four-ton hydraulic jack with an attached microwave 

drying system was developed for collapsible soils as part of a Ph.D. dissertation (Bowers, 1986). The 

technique was successful in detecting collapsible soils and predicting the magnitude of additional 

settlement due to moisture increases in a relatively simple and reliable way. 

The behavior of collapsible gravels is controlled by the fine matrix in the gravel. Small quantities of 

fines (as little as 5 to 20 percent) are enough to control collapse behavior. Relatively successful in situ 

methods for evaluating the properties of collapsible gravels include plate-load bearing tests and prebored 

pressuremeter tests. Both methods are conducted in the natural dry conditions and then after wetting.

51 NUREG/CR-5738
5. Geophysical Investigations

Traditional investigative methods like the SPT can exhibit high blowcounts in gravelly soils, but once 

moisture is introduced or increased in the area the stiffness of the material may decrease drastically. 

Samples that are collected and reconstituted in the laboratory produce lower undrained cyclic stress 

results than measured from in situ frozen samples, indicating a change in the natural soil characteristics 

after reconstitution. Sampling by in situ freezing may be an alternative to sample these kinds of soils and 

transport them to the laboratory without disturbance. 

5 GEOPHYSICAL INVESTIGATIONS 

The three primary objectives in the use of geophysical methods are the location and correlation of 

geologic features, such as stratigraphy, lithology, discontinuities, groundwater; the in situ measurement 

of elastic moduli and densities, and detection of hidden cultural features. Perhaps the best reference 

available on theory and applications for a wide variety of geophysical survey techniques is 

EM 1110-1-1802, Geophysical Exploration for Engineering and Environmental Investigations (DA, 

1995). The information presented in that manual is thorough and practical, and is useful to any 

individual or firm planning site reconnaissance or detailed geophysical characterization. The following 

discussion is general in nature; the reader is directed to EM 1110-1-1802 for specific guidance on 

contemporary geophysical survey practice. Internet users may find and download various manuals and 

other Corps of Engineers regulations, circulars, and Engineering technical letters at 

http://www.wes.army.mil/itl/cwgup/. 

In locating and correlating geologic features, indirect geophysical techniques are intended to supplement 

direct methods insofar as is practical. There is no substitute for a direct assessment of site conditions, 

i.e., borings, pits, trenches, etc. Borings or test excavations should be used in conjunction with 

geophysical interpretations (or if necessary to calibrate or correct them). If used in this manner, 

geophysical methods offer both economic advantages and the ability to rapidly explore large subsurface 

volumes with adequate accuracy. By judicious planning, the number of borings required for subsurface 

definition can be greatly reduced if the proper geophysical methods are chosen to supplement the direct 

investigational program (Ballard and McLean 1975). 

Geophysical methods may involve measurement of: seismic wave amplitude as a function of time, 

electrical conductivity or resistivity, electromagnetic radiation, radioactive radiation, magnetic flux 

density, and gravitational pull. These measurements can be obtained either by passive or by active 

techniques. Active techniques give more accurate information since the direct measurement or response 

of the subsurface materials to an introduced energy is collected. Passive measurements record the 

strength of various fields or changes in field strength which are always present, like gravity or magnetic fields. Assumptions are necessary for the interpretation of passive techniques and these assumptions can 

introduce ambiguity. 

Geophysical survey methods can be divided in non-contacting techniques, surface techniques, and 

downhole survey methods. Non-contacting techniques are generally less expensive, faster, and easier to 

use. Some times these surveys can even be performed by a single person and provide variability 

information on shallow rock or soil deposits. Non-contacting methods include techniques like ground 

conductivity, magnetic techniques, and GPR (ground penetrating radar). 

A single geophysical method rarely provides enough information about subsurface conditions to be used 

alone. Each method typically responds to several different physical characteristics of earth materials, and

NUREG/CR-5738 52
5. Geophysical Investigations

correlation of data from different methods has been found to provide the most meaningful results. Some 

degree of redundancy must be built into any well-planned site investigation. Certain methods may be 

useful under one set of subsurface conditions but offer little or no information in others. As with direct 

methods, planning, data acquisition, and interpretation phases of any investigational program using 

indirect methods are best performed by qualified personnel. 

In situ values of the elastic moduli and densities are required to solve many foundation and soil-structure 

interaction problems. These values are particularly important for wave propagation analyses and where 

soil-structure interaction is a dominant factor in the response of a structure to dynamic loadings. 

Foundations for reactor containment vessels, subject to earthquake excitation, are examples of 

applications where in situ elastic moduli are sometimes required for design or safety analyses. 

As a background for the use of geophysical methods, four general observations pertaining to these 

methods collectively should be made as listed in Schmidt et al., (1976): 

"(1) Geophysical surveys utilize both active and passive measurement techniques. In an active 

mode, some form of energy is introduced into the subsurface and the effect on the energy or the 

response of subsurface materials to energization is measured. Active measurement techniques 

usually provide the greatest accuracy. Passive measurements simply record the strengths of various 

fields or changes in field strength which are always present. Analytical assumptions that introduce 

ambiguity in the results are necessary for interpretation. 

"(2) Precision of measurements is high in all methods, but accuracy in the interpretation and 

inferences drawn from the measurements depends very much on the experience of the interpreter. 

All methods are inherently subject to lower accuracy due to interpretation as distance increases 

between the energy or field source of interest and the detecting sensors, especially in those methods 

based on field strength measurements (passive mode). 

"(3) Resolution capability of subsurface characteristics varies widely among geophysical methods 

when surveys are conducted conventionally. The parameters to be measured or inferred must be 

understood before a resolution dimension can be defined. Almost total resolution of any soil or strata 

parameter is possible if the survey is appropriately designed and time/cost requirements are not 

considered. One reasonable approximation is selection of measurement point separation on the order 

of the dimension of objects or strata changes to be resolved. 

"(4) Very few geophysical methods measure parameters directly used by the engineer (seismic and 

electrical methods may be exceptions), and all methods present the "averaged" effects of materials 

between and around the source and points of observation. Most results are based on interpretations 

that infer what kind of conditions would cause the measured parameter to have a certain value or to 

change in a certain way" 

The interpretation of geophysical data is based on the assumption that the various earth materials have 

distinct subsurface boundaries and are both homogeneous and isotropic. These assumptions are in many 

cases at variance with reality. In addition, the practice of computing shear (secondary, or s-) wave 

velocity from measured compression (primary, or p-) wave velocity through the assumption of a 

Poisson's ratio is not recommended. Borehole seismic surveys accommodate procedures to induce 

polarized shear waves that may be readily interpreted in motion records; surface refraction is generally 

performed using an explosive charge or an impact source, such as a hammer blow, to generate elastic

53 NUREG/CR-5738
5. Geophysical Investigations

waves in the ground. It is often difficult to distinguish shear waves recorded in the latter case, thus 

surface refraction is not considered the best method for shear wave velocity measurement. 

Table 4 is intended for use as a quick reference tool for the planners of foundation investigations. It is a 

tabulation of geophysical methods, their basic measurement parameters, engineering applications, 

advantages and primary limitations. 

To further simplify the selection of a geophysical method to fit a given engineering application, Table 5 

can be used as an aid in choosing the most effective geophysical method(s) to fit a specific engineering 

application. The matrix in the table is constructed in such a manner as to provide a subjective numerical 

rating system for the effectiveness of each method for a particular rating system. The five numerical 

ratings of 0, 1, 2, 3, and 4, which are explained in the note in Table 5, can then be used as an aid for 

planning an effective and economical site investigation. A rating of 4 for the combination of a given 

method indicates that the method is well developed, practical for use, and likely to give good results. 

5.1 Spectral Analysis of Surface Waves 

The Spectral Analysis of Surface Waves technique is widely applied to determine shear wave velocity 

profiles in a variety of applications (Stokoe and Nazarian, 1985; Stokoe et al., 1988). The SASW method 

is used for in situ evaluation of elastic moduli and layer thicknesses of soil and pavement profiles 

(Gucunski and Woods, 1991) and for large areal coverage in terrain with minimal relief. The technique 

has the advantage in that it is performed from the surface, and a simple procedure and test setup are 

required. 

The SASW method consists of several phases: 1. collection of data in the field, 2. evaluation of the field 

or experimental Raleigh wave dispersion curve, and 3. inversion of the dispersion curve to obtain the 

shear wave velocity profile. The common receivers midpoint (CRMP) geometry and the common source 

(CS) geometry are the two most common source-receivers setups for SASW practice. In the CRMP 

method, the source and the receiver are located at the same distance from an imaginary line at opposite 

sides and in CS the source has a fixed location. 

The type of energy source and motion transducer needed for the SASW will depend on the objective for 

which they are deployed. Layered deep soil deposits require large, low frequency energy sources (such 

as heavy vibrators) and sensitive, low frequency transducers; small, impact-type energy sources and high

frequency motion detectors would be used for investigations of layered pavements. 

As the SASW technique has evolved through time, additional options have become available to collect 

and process the substantial quantities of test data that are typically generated. The original approach was 

based on data collection with a full-function, dual channel Fast Fourier Transform (FFT) analyzer. A 

computer was then used to compute a field dispersion curve from the phase data of the cross power 

spectrum and perform the required inversion process. Several software/hardware packages are now 

available for SASW applications. Commercial waveform processing software can be used with a PC to 

replace the FFT analyzer. Transient waveform digital recorders can be used to gather, digitize and store 

SASW field data and the data may be transferred later to a PC with the necessary software to finish the 

dispersion and inversion operations of the FFT. These packages are compatible with IBM or Apple 

Macintosh PC's and perform all functions including data acquisition and waveform processing. The user 

may more customize an approach and upgrade capabilities as more software versions become available. 

SASW techniques have advanced from using dual to multi-channel analyzers of up to 64 channels and 

equipment will likely accommodate more in the future.

NUREG/CR-5738 54
Table 4 Applications of Selected Geophysical Methods for Determination of Engineering Parameters 

Geophysical Method Basic Measurement Application Advantages Limitations 

Surface

Refraction (seismic) 

Reflection (seismic)

Rayleigh wave 

dispersion 

Vibratory (seismic) 

Reflection profiling 

(seismic-acoustic)

Travel time of 

compressional waves 

through subsurface 

layers 

Travel time of 

compressional waves 

reflected from 

subsurface layers 

Travel time and period 

of surface Rayleigh 

waves 

Travel time or 

wavelength of surface 

Rayleigh waves 

Travel times of 

compressional waves 

through water and 

subsurface materials 

and amplitude of 

reflected signal

Velocity determination of 

compression wave through 

subsurface. Depths to 

contrasting interfaces and 

geologic correlation of 

horizontal layers 

Mapping of selected 

reflector horizons. Depth 

determinations, fault 

detection, discontinuities, 

and other anomalous 

features 

Inference of shear wave 

velocity in near-surface 

materials 

Inference of shear wave 

velocity in near-surface 

materials 

Mapping of various 

lithologic horizons; detection 

of faults, buried stream 

channels, and salt domes, 

location of buried man-made 

objects; and depth 

determination of bedrock or 

other reflecting horizons

Rapid, accurate, and relatively 

economical technique. 

Interpretation theory generally 

straightforward and equipment 

readily available 

Rapid, thorough coverage of 

given site area. Data displays 

highly effective

Rapid technique which uses 

conventional refraction 

seismographs 

Controlled vibratory source 

allows selection of frequency, 

hence wavelength and depth of 

penetration (up to 200 ft). 

Detects low-velocity zones 

underlying strata of higher 

velocity. Accepted method 

Surveys of large areas at 

minimal time and cost; 

continuity of recorded data 

allows direct correlation of 

lithologic and geologic changes; 

correlative drilling and coring can 

be kept to a minimum

Rapid, accurate, and relatively economical 

technique. Interpretation theory generally 

straightforward and equipment readily available. In 

saturated soils, the compression wave velocity 

reflects mostly wave velocities in the water, and 

thus is not indicative of soil properties. 

Rapid, thorough coverage of given site area. Data 

displays highly effective. In saturated soils, the 

compression wave velocity reflects mostly wave 

velocities in the water, and thus is not indicative of 

soil properties. 

Rapid technique which uses conventional refraction 

seismographs 

Controlled vibratory source allows selection of 

frequency, hence wavelength and depth of 

penetration (up to 200 ft). Detects low-velocity 

zones underlying strata of higher velocity. 

Accepted method 

Data resolution and penetration capability is 

frequency dependent; sediment layer thickness 

and/or depth to reflection horizons must be 

considered approximate unless true velocities are 

known; some bottom conditions (e.g., organic 

sediments) prevent penetration; water depth should 

be at least 15 to 20 ft for proper system operation

(Continued)

LAI

L0

LI' 

0 

0 

C) 

':1, 

rJQ 

0
Table 4 (Continued) 

Geophysical Method Basic Measurement Application Advantages Limitations 

Surface (Continued)

Electrical resistivity

Acoustic 

(resonance)

Ground penetrating 

radar(GPR)

Gravity 

Magnetic

Uphole/downhole 

(seismic)

00

Amplitude of 

acoustically coupled 

sound waves 

originating in an air

filled cavity 

Travel time and 

amplitude of a 

reflected 

electromagnetic wave 

Variations in 

gravitational field 

Variations of earth's 

magnetic field

Vertical travel time of 

compressional and/or 

shear waves

Complementary to refraction 

(seismic). Quarry rock, 

groundwater, sand and 

gravel prospecting. River 

bottom studies and cavity 

detection 

Traces (on ground surface) 

lateral extent of cavities

Rapidly profiles layering 

conditions. Stratification, 

dip, water table, and 

presence of many types of 

anomalies can be 

determined 

Detects anticlinal structures, 

buried ridges, salt domes, 

faults, and cavities 

Determines presence and 

location of magnetic or 

ferrous materials in the 

subsurface. Locates ore 

bodies 

Velocity determination of 

vertical P- and/or S-waves. 

Identification of low-velocity 

zones

Economical nondestructive 

technique. Can detect large 

bodies of "soft" materials

Rapid and reliable method. 

Interpretation relatively 

straightforward. Equipment 

readily available 

Very rapid method for shallow 

site investigations. On line 

digital data processing can yield 

"on site" look. Variable density 

display highly effective 

Provided extreme care is 

exercised in establishing 

gravitational references, 

reasonably accurate results can 

be obtained 

Minute quantities of magnetic 

materials are detectable

Lateral changes in calculated resistance often 

interpreted incorrectly as depth related; hence, for 

this and other reasons, depth determinations can be 

grossly in error. Should be used in conjunction with 

other methods, i.e., seismic 

Must have access to some cavity opening. Still in 

experimental stage - limits not fully established

Transmitted signal rapidly attenuated by water. 

Severely limits depth of penetration. Multiple 

reflections can complicate data interpretation.

Equipment very costly. Requires specialized 

personnel. Anything having mass can influence 

data (buildings, automobiles, etc). Data reduction 

and interpretation are complex. Topography and 

strata density influence data 

Only useful for locating magnetic materials. 

Interpretation highly specialized. Calibration on site 

extremely critical. Presence of any ferrous objects 

influences data

Borehole

Rapid technique useful to define 

low- velocity strata. 

Interpretation straightforward

Care must be exercised to prevent undesirable 

influence of grouting or casing

(Continued)

Electrical resistance of 

a volume of material 

between probes

Liq 

0 

0 

Zi 

0
Table 4 (Continued) 

Geophysical Method Basic Measurement Application Advantages Limitations 

Borehole (Continued) 

Crosshole (seismic) Horizontal travel time Velocity determination of Generally accepted as producing Careful planning with regard to borehole spacing of compressional horizontal P- and/or S- reliable results. Detects low- based upon geologic and other seismic data an and/or shear waves waves. Elastic velocity zones provided borehole absolute necessity. Shell's law of refraction must 

characteristics of sub- spacing not excessive be applied to establish zoning. A borehole deviation 

surface strata can be survey must be run. Requires highly experienced 

calculated personnel. Repeatable source required. 

Borehole Natural earth potential Correlates deposits, locates Widely used, economical tool. Log must be run in a fluid filled, uncased boring. 

spontaneous water resources, studies Particularly useful in the Not all influences on potentials are known 

potential rock deformation, assesses identification of highly porous 

permeability, and strata (sand, etc.) 

determines groundwater 

salinity 

Single-point Strata electrical In conjunction with Widely used, economical tool. Strata resistivity difficult to obtain. Log must be 

resistivity resistance adjacent to spontaneous potential, Log obtained simultaneous with run in a fluid filled, uncased boring. Influenced by a single electrode correlates strata and locates spontaneous potential drill fluid 

porous materials 

Long and short- Near-hole electrical Measures resistivity within a Widely used, economical tool Influenced by drill fluid invasion. Log must be run in 

normal resistivity resistance radius a fluid filled, uncased boring 

of 16 and 64 in. 

Lateral resistivity Far-hole electrical Measures resistivity within a Less drill fluid invasion influence Log must be run in a fluid filled, uncased- boring. resistance radius of 18.7 ft Investigation radius limited in low moisture strata 

Induction resistivity Far-hole electrical Measures resistivity in air- Log can be run in a Large, heavy tool 

resistance or oil-filled holes nonconductive casing 

Borehole imagery Sonic image of Detects cavities, joints, Useful in examining casing Highly experienced operator required. Slow log to 

(acoustic) borehole wall fractures in borehole wall. interior. Graphic display of obtain. Probe awkward and delicate. 

Determine attitude (strike images. Fluid clarity immaterial 

and dip) of structures 

0ý (Continued)

0-- CD 

0 

0 •r 

rQ 

Pe)A
Table 4 (Continued) 

Geophysical Method Basic Measurement Application Advantages Limitations 

Borehole (Continued)

C) 

00

Continuous sonic 

(3-D) velocity 

Natural gamma 

radiation 

Gamma-gamma 

density 

Neutron porosity 

Neutron activation 

Borehole magnetic 

Mechanical caliper

Time of arrival of P

and S-waves in high

velocity materials 

Natural radioactivity 

Electron density 

Hydrogen content 

Neutron capture 

Nuclear precession 

Diameter of borehole

Determines velocity of P

and S-waves in near vicinity 

of borehole. Potentially 

useful for cavity and 

fracture detection. Modulus 

determinations. Sometimes 

S-wave velocities are 

inferred from P-wave 

velocity and concurrently 

run nuclear logs through 

empirical correlations 

Lithology, correlation of 

strata, may be used to infer 

permeability. Locates clay 

strata and radioactive 

minerals 

Determines rock density of 

subsurface strata 

Moisture content (above 

water table) total porosity 

(below water table) 

Concentration of selected 

radioactive materials in 

strata 

Deposition, sequence, and 

age of strata 

Measures borehole diameter

Shear wave velocity definition questionable in 

unconsolidated materials and soft sedimentary 

rocks. Only P-wave velocities greater than 5,000 

fps can be determined

Widely used method. Rapid and 

relatively economical. Variable 

density display generally 

impressive. Discontinuities in 

strata detectable 

Widely used, technically simple 

to operate and interpret 

Widely used. Can be applied to 

quantitative analyses of 

engineering properties. Can 

provide porosity 

Continuous measurement of 

porosity. Useful in hydrology and 

engineering property 

determinations. Widely used 

Detects elements such as U, Na, 

Mn. Used to determine oil-water 

contact (oil industry) and in 

prospecting for minerals (Al, Cu) 

Distinguishes ages of 

lithologically identical strata 

Useful in a wet or dry hole

(Continued)

Borehole effects, slow logging speed, cannot 

directly identify fluid, rock type, or porosity. 

Assumes clay minerals contain potassium 

40 isotope 

Borehole effects, calibration, source intensity, 

chemical variation in strata affect measurement 

precision. Radioactive source hazard 

Borehole effects, calibration, source intensity, 

bound water, all affect measurement precision. 

Radioactive source hazard 

Source intensity, presence of two or more elements 

having similar radiation energy affect data 

Earth field reversal intervals under study. Still 

subject of research 

Must be recalibrated for each run. Averages 

3 diameters

(-'D 

0 

ZT 

0n

(A 

00
Table 4 (Concluded) 

Geophysical Method Basic Measurement Application Advantages Limitations 

Bnrehole (Cnntinupd)

Acoustic caliper

Temperature

Fluid resistivity

Tracers

Flowmeter

LA

Borehole dipmeter 

Borehole surveying 

Downhole flow 

meter

z 

L) 

00

Sonic ranging 

Temperature

Fluid electrical 

resistance

Direction of fluid flow 

Fluid velocity and 

quantity 

Sidewall resistivity 

Azimuth and 

declination of borehole 

drift 

Flow across the 

borehole

Measures borehole diameter 

Measures temperature of 

fluids and borehole 

sidewalls. Detects zones of 

inflow or fluid loss 

Water-quality 

determinations and auxiliary 

log for rock resistivity 

Determines direction of fluid 

flow 

Determines velocity of 

subsurface fluid flow and, in 

most cases, quantity of 

flow 

Provides strike and dip of 

bedding planes. Also used 

for fracture detection 

Determines the amount and 

direction of borehole 

deviation from the vertical 

normal 

Determines the rate and 

direction of groundwater 

flow

L argeT ranql Otseful with highly 

irregular shiapes 

Rapid, economical, and generally 

accurate

Economical tool

Economical

Interpretation is simple

Useful in determining 

information on the location and 

orientation of primary 

sedimentary structures over a 

wide variety of hole conditions 

A reasonably reliable technique. 

Method must be used during the 

conduct of crosshole surveys to 

determine distance between 

seismic source and receivers 

A reliable, cost effective method 

to determine lateral foundation 

leakage under concrete 

structures

Requires fluid filled hole and accurate positioning

None of importance

Borehole fluid must be same as groundwater 

Environmental considerations often preclude use of 

radioactive tracers 

Impeller flowmeters usually cannot measure flows 

less than 2 - 3 ft/min 

Expensive log to make. Computer analysis of 

information needed for maximum benefit 

Errors are cumulative, so care must be taken at 

each measurement point to achieve precise data 

Assumes flow not influenced by emplacement of 

borehole.

LA 

P 

0 

0 

C, 

0q 

o,
C) 

00 

ON CD

0 = Not considered applicable 

1 = Limited 

2 = Used or could be used, but not best approach 

SAirborne or inhole survey capability not considered.

3 = Excellent potential but not fully developed 

4 = Generally considered as excellent approach; state of art well developed 

A = In conjunction with other electrical and nuclear logs

Table 5 Numerical Rating of Geophysical Methods to Provide Specific Engineering Parameters' 

r) C 

,,, e • o -- o . - C ." - "o 0 .c 

.00 M C 0. CO 

~ i ~ .20 0C a 0 'rZ W 

Jd c a 0 -- " 0 E -- 0 0 0 0 C'- -- D ., G p i 0 M. - - o c a N 2 0 (a> 

R4 ) 2 c 0 2 cc Rfeinsi 1 4 i) 0 0 0 0 0 2 C 0 3 03 0 

R lgw 2 eie10 2 0 0 0 0 0 C0 c .0 0 1 0 0 0 0 a O 

ibrator(seiphsmicalethd00 > 4 C4 0 0 T Ch 0 2 1 0 0 0 0)0 0 0 2 2 0 2 2 3 

Reflectionprof(seismic c 4401 3 42100 2202 0 024323 0 

CEflectriclsenil 4000001 4 w 40000 01 00 0 0 3 3! 0 

Eyletriwalredistivit3 10220021 3 02 1000020 0 012 0 

Acoustic~~~~~~~ ~L (rsnneM 0 0 r 

Geond p hysraingraarl Meho 0 ) =W 0 - M 0 J 3' W S a. C 0 0 0 2 is Ca 00 'M U. 3 3 O M 

eractiorn(seismic) 4 04 0 4 21 3 4 2 1 0 0 2 2 0 2 0 0 2 2 3 2 2 3 0 

GRefecion (simc 4 0 0 0 0 0 14 4 0 0 0 0 0 2 0 1 0 0 2 0 4 3 3 3 0 

Rayletigh wav diprso 1 0 2 2 0 0 13 02 1 0 0 0 0 0 0 0 0 1 0 0 0 1 24 0 

Vibraorydonhl (seismic) 2 0 4 4 4 o 1 3 0 2 1 0 0 0 0 0 0 0 0 2 2 1 2 23 0 

Reflectionprofiling (seismic-acoustic) 4 0 0 0 0 0 1 4 4 0 0 0 0 0 0 0 0 0 0 3 0 4 3 3 4 0 

Electricalpotential 0 0 0 0 0 1 0 0 0 0 1 233 0 3 3 3 4 0 

Electrical resistivity 3 0 0 0 0 0 1 3 2 0 0 0 2 1 3 0 2 2 0 3 2 0 4 44 0 

Acoustic (resonance) 00 00 0 00 0 00 00 0 0 000 3 00 00 0 40 0 

Ground penetrating radar' 30 00 00 1 3 20 00 2 3 300 2 03 03 3 33 0 

Electromagnetic 4 0 0 0 0 0 3 4 1 0 0 0 1 2 3 2 0 0 0 0 3 2 1 3 0 

Gravity 3000000 0 100000000 0 0401333 0 

Magneticb 00 00 0 00 0 10 00 00 0 00 0 00 0 02 2T4 0 

BoreholeI 

Uphole/downhole (seismic) 44 44 4 41 4 0 210 02 2 02 0 0 12 3 022 0 

Crosshole (seismic) 44 44 4 41 4 22 10 02 2 02 0 03 23 3273 0 

Crosshole acoustic 44 44 4 01 3 4 0 0010 3 00 0 0 33 3 30 0 

Crosshole resistivity 30 00 0 01 3 10 00 10 30 3 0 0 02 3 30 0 

Borehole spontaneous potential 20 0 00 0 4 4 4 20 00 0oTT24 0 0 1 0 22 1 3 0 

Single-point resistivity 2010ý00 04 4 1 00 0 01 1T24 0 0 1 01 1 1 2 0 

(Continued) 8Numerical rating refers to applicability of method in terms of current use and future potential:

0 

YQ 

0 

CD
Table 5 (Concluded) 

(U 0 

CU V)~ 00 0" M -:t o 

0 - . • -E- 0. 0o 

BorehleD (Cntnud 

-0 CO0 C 0 1 2 

I0 0 M 0 3 2 W 

Boeoeiagr cuti 0 2 (U 0 1 u 0 2 0 ~ 2 0 1 . 0 2 2 3 C 

-) (UD 

> > m 0 .2 M 0 4- 3 . G C 0) 4 4 i 3 0 0 20 2 C 0 

N t 0 0 p s 2A dA 0) W 

Geophnysica l Method 2A CO M 0 0 0 3 5 1 C 0 1 . l! 0 2 3a 3 W 0 X 0 . 0. J 4 

Borehole gravit000 0 

Mechand short 0 0 0 0 0 40 1 1 0 0 0 4 3 0 2 0 0 0 0 1 1 2 4 0 

Later aliity 2 0 0 0 0 0 3 4 1 1 0 0 0 4 0 0 0 1 2 0 

Inductinres t 2 0 0 0 0 0 4 4 0 0 1 0 0 0 4 3 0 2 0 0 0 0 1 2 4 0 

Boresimagery a0 0 0 0 0 2 31 2 0 00 02 2 3 0 

Intracersh1)vorityr2 4 2 2 2 2 4 1 1 1 1 00 0 0 0 00 1 0 3 2 2 0 

Natural gamma radiation 20 00 00 4 4 1 2 0 0 3A1A 3A 22A 1 0 0 0 3A 1 1 4 0 

Gamma-gammadensity 3A 0 0 0 0 4 0 1 3A0 0 2A 3A 2A 0 0 0 00 33A 2 1 0 

Neutron porosity 2A 0 0 0 0 0 4 4 1 3A 0 3A 3A 0 0 0 00 0 3A 2 1 4 0 

Neutron activation 2A 00 0 0 03 1 1 0 0 02A 23A 0 0 2 0 10 10 0aT 0 

Borehole gravity 1 0 0T 0 0 00 0 0 0 0 0 0 0 0 2 4 0 0 

Mechanical caliper 0 0 00 001 0 10 00 00 0 00 0 40 00 00 0W 0 

Acoustic caliper 0 00 0 001 0 10 00 00 0 00 0 21 00 0 00 0 

Temperature 0 000000 0 0 0 7 4 1 0 T 4 4 2 0 0 0 0 1 2 1 0 

Fluid resistivity 00 0 0 000 1 0 1 0 0 14 4 44 0 0 00 03 1 1 0 

Tracers 0 0 0 T 0 0 W 0 W00WT00 W 2 0 4 4 0 1 00 0 30 0 

Flowmeter 00 0 0000 0 0 00 02 2 20 4 4 02 00 0 20 0 

Sidewall sampling 4 000 0 04 4 1 42 044 2 00 0 02 2 21 oT4 0 

Fluid sampling 00 00 000 0 0 0041 oT 0 4 44 2 00 00 0 00 0 

Borehole dipmeter 0 0 0 0 0 0 24 0 0 0 0 0 0 0 0 0 0 0 2 0 0 1 2 

Borehole surveying 0 0F0 0 0 0 0 0 0 0 0 0 0 00 0 00 0 0 000000 4 

a'u era 1 4ou LUI AU fIjI~UIL 4I~IV +I +1 +; I~~40 Nilumer0cal rating rcser ed applicablILy 0 me- ;ocu . - a" u Excerm llent pot 0 = Not considered applicable 3 = Excellent pot

1 = Limited 

2 = Used or could be used, but not best approach 

Airborne or inhole survey capability not considered.

ential but not fully developed

4 = Generally considered as excellent approach; state of art well developed 

A = In conjunction with other electrical and nuclear logs

C0 

00

(A 

P 

C) 

0 

(D
6. In Situ Physical Testing

5.2 Measurement of Strain-dependent Properties 

Most of the geophysical survey techniques discussed or presented in tables thus far measure in situ 

values of low-strain dynamic response characteristics, such as modulus and damping, within a localized 

region around the energy source. Laboratory tests on undisturbed or reconstituted specimens have been 

used to determine strain-dependency of various parameters in controlled environments, and these trends 

are typically extrapolated to predict in situ response in natural deposits. For critical projects, such as 

nuclear power facility foundations, sophisticated numerical analyses may be applied and it may be 

justifiable to determine variability of dynamic response parameters over larger volumes of material that 

better represent in situ behavior. Large-scale in situ dynamic testing techniques have been developed that 

capture both low- and large-strain dynamic response data; two of the more well-developed are: the in situ 

impulse test (Troncoso, 1975) and the cylindrical in situ test (CIST) (Wilson, Brown, and Schwarz, 

1978). Both are crosshole geophysical methods, requiring installation and instrumentation of several 

boreholes with the concomitant expense. 

The in situ impulse test involves generation of controlled shear waves within a source borehole and 

several receiver boreholes spaced to take advantage of decreased strain with distance from the source. 

The method is capable of providing shear wave velocities over a range of shear strains from 1 0 ' to 

10-1 percent. The energ'y source consists of a guided hammer which is dropped 30 cm onto an anchor that 

is clamped to couple the energy into the wall of the borehole; a spring receives the hammer blow and 

shapes the input shear wave (Troncoso, 1975). The method is reported to be effective to depths up to 

200 feet (61 m) in most soils. Recent study of this procedure, popularly known as the large-strain 

seismic cross-hole test, is detailed by Salgado et al. (1997). This reference includes discussion of proper 

interpretation techniques, as well as a case history of its application at a Department of Energy site for 

determination of site-specific shear modulus degradation relationships. Low-strain results are favorably 

compared with those obtained using shear wave velocity measurements from seismic cone penetrometer 

tests. 

An alternative method to the in situ impulse test, the cylindrical in situ test, was first developed to 

investigate soil response to blast loads. The main difference between the two large-scale in situ tests is 

the energy source: the CIST source is a continuous, vertical line charge of high explosive installed central 

to the array of radially spaced receiver holes. The charge may be detonated in a delayed, controlled 

fashion to invoke other responses besides that associated with blast effects, and numerical models of the 

site in question may be accurately calibrated by matching received and predicted response (Wilson, 

Brown, and Schwarz, 1978). 

6. IN SITU PHYSICAL TESTING 

6.1 In situ Tests - General 

In situ tests are often the best means of determining the engineering properties of subsurface materials 

and, in some cases, may be the only way to obtain meaningful results. Some materials are hard to sample 

and transport, while keeping them representative of field conditions, because of their softness, their lack 

of cohesion, or their composition. In situ techniques offer an option for appropriate evaluation of soils 

and rock that cannot be sampled for laboratory analysis. Table 6 lists several of the most commonly 

practiced in situ tests and their purposes. Several techniques will be discussed in some detail below.

NUREG/CR-5738 62
6. In Situ Physical Testing

Table 6 In Situ Tests for Rock and Soil (adapted from 

of the Army, 1984)

EM 1110-1-1804, Department

Applicability to 

Purpose of Test Type of Test Soil Rock 

Shear strength Standard penetration test (SPT) X 

Field vane shear X 

Cone penetrometer test (CPT) X 

Direct shear X 

Plate bearing or jacking X Xa 

Borehole direct shearb X 

Pressuremeterb X 

Uniaxial compressiveb x 

Borehole jackingb X 

Bearing capacity Plate bearing X Xa 

Standard penetration X 

Stress conditions Hydraulic fracturing X X 

Pressuremeter X Xa 

Overcoring X 

Flatjack X 

Uniaxial (tunnel) jacking X X 

Borehole jackingb x 

Chamber (gallery) pressureb X 

Mass deformability Geophysical (refraction) X X 

Pressuremeter or dilatometer X Xa 

Plate bearing X X 

Standard penetration X 

Uniaxial (tunnel) jacking X X 

Borehole jackingb x 

Chamber (gallery) pressureb x 

Relative density Standard penetration X 

In situ sampling X 

Liquefaction susceptibility Standard penetration X 

Cone penetrometer test (CPT) X 

Shear wave velocity (vs) 

a Primarily for clay shales, badly decomposed, or moderately soft rocks, and rock with soft seams. 

b Less frequently used.

63 NUREG/CR-5738
6. In Situ Physical Testing

Interpretation of in situ test results in soils, clay shales, and moisture-sensitive rocks requires 

consideration of the drainage that may occur during the test. Consolidation during soil testing makes it 

difficult to determine whether the results correspond to unconsolidated- undrained, consolidated

undrained, consolidated-drained conditions, or intermediate conditions between these limiting states. 

Interpretation of in situ test results requires complete evaluation of the test conditions and the limitations 

of the test procedure. 

Rock formations are generally separated by natural joints and bedding planes (discontinuities), resulting 

in a system of irregularly-shaped blocks that respond as a discontinuum to various loading conditions. 

Response of a jointed rock mass to imposed loads involves a complex interaction of compression, 

sliding, wedging, rotation, and possibly fracturing of individual rock blocks. Individual blocks generally 

have relatively high strengths, whereas the strength along discontinuities is normally reduced and highly 

anisotropic. Commonly, little or no tensile strength exists across discontinuities. As a result, resolution 

of forces within the system generally cannot be accomplished by ordinary analytical methods. 

Large-scale in situ tests tend to average out the effect of complex interactions. In situ tests in rock are 

generally expensive and should be reserved for projects with large concentrated loads. Well conducted 

tests, however, may be useful in reducing overly conservative, costly assumptions. Such tests should be 

located in the same general area as a proposed structure and test loading should be applied in the same 

direction as the proposed structural loading. In situ rock tests are performed to determine in situ stresses 

and deformation properties of the jointed rock mass, shear strength of jointed rock masses or critically 

weak seams within the rock mass, and residual stresses along discontinuities or weak seams in the rock 

mass. In situ testing performed in weak, near surface rocks include: penetration testing, plate loading 

testing, field geophysical techniques, and pressuremeter testing. 

Table 7 lists in situ tests that are useful for determining the shear strength of subsurface materials. In situ 

shear tests are discussed and compared by Nicholson (1983) and Bowles (1996). Direct shear strength 

tests in rock measure peak and residual direct shear strength as a function of normal stress on the shear 

plane. Direct shear strength from intact rock can be measured in the laboratory if the specimen can be 

cut and transported without disturbance. The suggested in situ method for determining direct shear 

strength of rocks (test preparation, consolidation, shearing and calculation procedures) is described in the 

RTH 321-80, "Suggested Method for In Situ Determination of Direct Shear Strength," (Handbook). 

6.2 In Situ Soil Testing 

6.2.1 The Standard Penetration Test (SPT) 

The standard penetration test (Figure 9) is a soil index test used to obtain the resistance to penetration by 

counting the number of blows required to drive a steel tube of specific dimensions into the subsoil a 

specified distance using a hammer of a specified weight (EM 1110-1-1906, DA, 1996). The SPT can be 

used in relatively clean medium -to-coarse sands and fine gravels with a variable amount of moisture, and 

in saturated or nearly saturated cohesive soils. Non-saturated cohesive soils and saturated silty sands can 

produce misleading N-values (the standard penetration resistance, or number of blows required to 

penetrate the final 12 inches of an 18-inch drive). Typical SPT testing and sampling intervals are of 

0.6 to 1.5 m (2 to 5 feet) in uniform strata and whenever there is a change of strata. Control of the 

hammer drop can be by manual, automatic, semiautomatic, or trip-hammer drop systems. 

Borehole disturbance can affect SPT results dramatically, and may reduce N values to a fraction of the 

value that would be obtained in undisturbed ground. SPT blow count data can also be affected by the 

penetration interval, the sampling tube design, the number of turns of rope on the cathead winch used to

NUREG/CR-5738 64
6. In Situ Physical Testing

Table 7 In Situ Tests to Determine Shear Strength 

Department of the Army, 1984)

(adapted from EM 1110-1-1804,

For 

Test Soils Rocks Reference Remarks 

Standard X EM 1110-2-1906 Use as index test only for strength. Develop 

penetration Appendix B local correlations. Unconfined compressive 

strength in tsf is often 1/6 to 1/8 of N-value 

Direct shear X X RTHa 321-80 Expensive; use when representative 

undisturbed samples cannot be obtained 

Field vane shear X ASTM D 2573-94 Use strength reduction factor 

Plate bearing X X ASTMb Designation Evaluate consolidation effects that may occur 

D 1194 during test 

ASTM SPT 479c 

Uniaxial X RTHa 324 Primarily for weak rock; expensive since several 

compression sizes of specimens must be tested 

Cone X Schmertmann (1978); Consolidated undrained strength of clays; 

penetrometer Jamiolkowski et al. requires estimate of bearing factor, Nc 

test (CPT) (1982) 

a Rock Testing Handbook. 

b American Society for Testing and Materials. 

c Special Technical Publication 479.

65 NUREG/CR-5738
6. In Situ Physical Testing

raise the safety hammer between blows, variations on drop height, energy delivered to the sample tube, 

or split-spoon, in situ stress conditions, faulty equipment, and overboring. The suggested approach is to 

follow standard procedures, to be aware of the potential errors and error sources that can affect the 

technique, and take errors into account when collecting and interpreting SPT data. EM 1110-1-1906 

(DA, 1996) describes the STP method and suggests modifications to the interpretation procedure. 

The N-value has been empirically correlated with liquefaction susceptibility under seismic loadings 

(Seed, 1979). The N-value is also useful for pile design. In cohesive soils, the N-value can be used to 

determine where undisturbed samples should be obtained. The N-value can also be used to estimate the 

bearing capacity (Meyerhof, 1956; Parry, 1977) and the unconfined compressive strength (Mitchell, 

Guzikowski, and Villet, 1978) of soils. The split-spoon sampler driven during an SPT recovers disturbed 

soil that may be used for visual classification and laboratory index testing, including determination of 

natural water content. Longer and larger diameter samplers are commercially available for recovery of 

coarse-grained soils. 

6.2.2 Becker Penetration Test (BPT) 

The Becker hammer drill (Harder and Seed, 1986) is essentially a double-acting diesel pile driver 

specifically designed for penetration of frozen or large-particled soils. The operation of the drill has been 

adapted to perform an in situ penetration test that has been compared (by empirical correlation of 

blowcounts, not by physical procedures and test conditions) to the SPT in sandy soils. When performed 

using double-walled casing and reverse circulation by air, the Becker hammer drill produces highly 

disturbed samples of subsurface materials by means of a cyclone separator. The Becker Penetration Test 

(BPT) is not a standard test but is an alternative method to drill and sample in gravelly, bouldery soils 

and obtain their engineering characteristics. The BPT is not listed in the summary tables, since it is 

necessary to empirically convert BPT blow counts (obtained per foot of continuous penetration using a 

plugged casing) to equivalent SPT blow counts for correlation to field performance data on liquefaction 

resistance and residual shear strength. Limitations include sample disturbance and possible significant 

alteration of the in situ stress conditions during drilling. Appendix H of EM 1110-1-1804 (DA, 1995) 

describes the application of the Becker Penetration Test. 

6.2.3 Direct Shear Tests 

In situ direct shear tests are expensive and are performed only where doubt exists about available shear 

strength data and where thin, soft, continuous layers exist within strong adjacent materials. The direct 

shear test measures peak and residual strength as a function of stress normal to the shear plane. Results 

are usually employed in limit equilibrium analysis of slope stability problems or for stability analysis of 

foundations for large structures such as dams. In situ direct shear tests may be necessary where field 

evidence suggests that only residual strengths can be relied on, either in a thin layer or in a mass, because 

of jointing, slickensiding, or old shear surfaces. Few in situ direct shear tests are performed on soils; 

they may be justified in clay shales, very soft rock, and on thin, continuous, weak seams that are difficult 

to sample. Methods for performing in situ strength tests on rock are described in Zeigler (1976) and Das 

(1994). 

6.2.4 Field Vane Shear Tests 

The field vane test is an in situ test used to measure the undrained shear strength of clays. The technique 

was developed to avoid sample disturbance effects common to soft materials by performing the test in the 

field. The vane, which consists of four blades in a cross shape, is pushed into the soil to the desired

NUREG/CR-5738 66
6. In Situ Physical Testing

depth for testing and the torque needed to rotate it is measured. The shear strength of the soil is 

calculated from the torque and the geometry of the vane. A review of field vane testing is given by 

Chandler (1988). The test can be performed in the field either from the ground surface or from the 

bottom of a borehole following the ASTM D 2573-94, "Standard test method for field vane shear tet in 

cohesive soil," protocol or, at a reduced scale, in the laboratory. The test may be affected by such factors 

as soil type, permeability, strength anisotropy, disturbance when inserting the vane, amount of time 

between the insertion of the vane and the beginning of the test, the rate of rotation or strain, and failure of 

soil around the vane. Technique and equipment improvements have developed correction factors or 

equipment modifications to deal with many of the above issues (Merrifield, 1980). Field vane tests 

performed in boreholes can be useful in soft, sensitive clays that are difficult to sample. However, they 

may give results that indicate strengths that are too high. Factors to correct the results are discussed in 

Mitchell, Guzikowski, and Villet (1978). The test has been standardized by ASTM as D 2573. 

6.2.5 Plate Bearing Tests 

Plate bearing tests can be made on soil or soft rock. Because of their cost, such tests are normally 

performed during advanced design studies or during construction. They are used to determine subgrade 

moduli and occasionally to determine strength. Plate loading tests are used to determine the stiffness, 

compressibility, and other properties of hard-to-sample soils, granular soils, and fractured weak rocks. 

The test is performed by applying successive load increments until the soil or rock fails or until the soil 

resists several times the proposed designed load. When testing shear strength or bearing capacity of 

cohesive soils, the plate test is performed by applying a constant load to give a constant rate of 

penetration from which the undrained shear strength is calculated. Small downhole plate-loading tests 

can also be performed (Wrench, 1984). The need for reliable engineering properties of rocks and the 

lack of other methods to obtain them make plate testing for rocks an efficient and cost-effective 

approach. It is recommended that they be performed at the end of a site characterization study or as part 

of a supplementary study. The location and number of tests will depend on the soil or rock mass 

variability and properties as determined by other tests and visual observations. 

6.2.6 Pressuremeter Test 

The pressuremeter test can be used in all types of soil and weak rocks to measure strength and 

compressibility parameters. The pressuremeter test is used in overconsolidated clays to measure 

undrained strength, shear modulus, and coefficient of earth pressure at rest, K,. Pressuremeters designed 

for higher pressure application in hard soils or rocks can be called dilatometers. The pressuremeter 

derives information on stiffness and strength of weak materials by measuring the relationship between 

applied radial pressure and the resulting deformation. The pressuremeter test may be used to infer 

parameters such as undrained shear strength (Marchetti, 1980), unit weight (Marchetti and Crapps, 

1981), effective angle of friction (Marchetti, 1980), drained constrained modulus (Marchetti, 1980), 

elastic modulus, and the very small-strain shear modulus, Ga. Determination of in situ pore pressure 

and horizontal stress can be obtained in sands (Lutenegger and Kabir, 1988; and Robertson, Campanella, 

and Gillespie, 1988), in normally consolidated young clays (Lunne et al., 1990), in soft and medium to 

stiff clays (Briaud and Miran, 1992) 

6.2.6.1 Borehole Pressuremeter. The borehole pressuremeter can be used in cemented very hard soils, 

gravelly soils, or rocks. The borehole pressuremeter is lowered into a smooth-walled borehole to the 

desired position and then inflated. The radial displacement is then measured either by a fluid-filled 

measuring cell or using gas (e.g., Oyo Elastmeter 2TM) and electronically measuring the displacement with 

two opposing measuring arms.

67 NUREG/CR-5738
6. In Situ Physical Testing

6.2.6.2 Self-boring Pressuremeter. This pressuremeter is used only for soft soils and cannot be used in 

cemented very hard soils, gravelly soils, or rocks. This pressuremeter includes an internal cutting 

mechanism at its base and is pushed hydraulically. Cuttings are flushed by fluid through the center of the 

probe as it advances. There are several versions of this penetrometer: The Cambridge self-boring 

penetrometer, the Rock self-boring penetrometer (Clarke and Allan, 1989), and the French Pressiometre 

Autoforeur (PAF) (Baguelin et al., 1972). 

6.2.6.3 Displacement Pressuremeter. Two models of displacement pressuremeters are available: the 

push-in pressuremeter (PIP), mainly used in offshore investigations (Henderson, Smith, and St. John, 

1979), and the cone-pressuremeter (Withers, Schaap, and Dalton, 1986) which is a displacement 

measuring mechanism mounted on a cone penetrometer, which will be described in a subsequent section. 

6.2.6.4 Marchetti Dilatometer. As defined previously, the Marchetti dilatometer is a pressuremeter. 

This test (DMT) (Marchetti, 1980) is used to calculate horizontal stress, dilatometer modulus, and pore 

pressure indices of preferably normally consolidated clays and uncemmented sands. The Marchetti blade 

can be pushed from the surface without a borehole, avoiding drilling disturbance. A DMT sounding can 

be performed in a short time and its results can be processed on a portable computer in the field. 

6.2.6.5 Cone Penetrometer Test. The Cone Penetration Test (CPT) is an in-situ testing method for 

evaluating detailed soil stratigraphy as well as estimating geotechnical engineering properties 

(Schmertmann, 1978). The basic, electrical CPT involves hydraulically pushing a 1.4-inch-diameter 

instrumented probe into the earth while performing two measurements: cone tip bearing resistance and 

sleeve friction resistance. The cone penetrometer test (CPT) is very useful for detecting soft or weak 

layers and in quantifying undrained strength trends with depth. The probe is normally pushed from a 

special heavy duty truck but can also be performed from a trailer or drill rig. Because of the weight of 

the truck or trailer needed to conduct CPT borings, access to soft ground sites may require a special , all

terrain tracked vehicle. Olsen (1994) gives a comprehensive description of the CPT in its various forms 

and applications. 

Soil type may be determined by empirical correlation to CPT penetration and frictional resistances 

(Douglas and Olsen, 1981), which should be supported by direct evidence from adjacent borings. Once 

soil type is known, the undrained strength can be estimated for clays (Jamiolkowski et al., 1982; 

Schmertmann, 1970), and the relative density (and friction angle) estimated for sands (Durgunoglu and 

Mitchell, 1975; Mitchell, Guzikowski, and Villet, 1978; Mitchell and Lunne, 1978; Schmertmann, 1978). 

For clays, a bearing factor, N., must be estimated in order to calculate the undrained strength from the 

cone resistance and should be close or slightly greater than the sleeve friction resistance if the soil is not 

sensitive or remolded (Douglas and Olsen, 1981). The calculated undrained strength, as well as the 

change of undrained strength with depth, can be used by means of CPT techniques to estimate the 

overconsolidation ratio (OCR) (Schmertmann, 1978). For sands, the relative density can be estimated if 

the overconsolidation conditions (i.e., lateral stress ratio) and vertical effective stress are known. The 

friction angle can also be estimated but also depends on the cone surface roughness and the assumed 

failure surface shape (Durgunoglu and Mitchell, 1975). Empirical charts for estimating seismically 

induced pore pressures (liquefaction) have been developed based on cone penetration measurements 

performed at sites at which earthquakes have occurred. These charts are similar to those developed for 

SPT blowcounts. 

The basic Cone Penetrometer Test (CPT) consists of pushing a cone of specific characteristics and 

dimensions into the ground at a constant speed of approximately 2 cm/s and measuring the amount of 

force required for penetration due to end bearing and side friction forces. Cone resistance and side

NUREG/CR-5738 68
6. In Situ Physical Testing

friction can be measured either by electrical or mechanical means. Originally used to locate and 

characterize sand layers in soft clays, CPT methods can be used to acquire detailed subsurface 

stratigraphic information, soil type information, pore pressure measurements, undrained strength for 

clays, and relative density for sands. Current standards and procedures are detailed in ASTM D 3441-94, 

"Standard test method for deep, quasi static, cone and friction-cone penetration test of soil." 

The addition of piezocones to the CPT to measure pore water pressure has been of great utility, 

especially when characterizing soft cohesive deposits. By being able to measure pore pressure, the CPT 

can also determine the following: 

"• Profiling - location of thin granular layers in soft cohesive deposits, which is very important to 

determine the consolidation rate of those kinds of deposits. 

"* Soil type identification - The ratio between net cone resistance and the excess pore pressure, can be 

correlated to soil type. 

"* Determining static pore pressure - this can be accomplished in granular soils and estimated in clays 

by waiting for full dissipation of the excess pore pressure provoked by penetration. 

* Determination of in situ consolidation characteristics - the horizontal coefficient of consolidation 

(CJ) in clays can be obtained by measuring pore pressure dissipation as a function of time after 

stopping the cone. 

Specialized CPT equipment has also been developed for environmental site assessment, for example the 

Tri-Service (Army, Navy, Air Force) Site Characterization and Analysis Penetrometer System (SCAPS) 

(Koester et al., 1993), which is used to detect various underground contaminants. On-site 3-dimensional 

visualization of the subsurface stratigraphy and regions of potential contamination are quickly delineated 

using the SCAPS rigs with custom software and onboard computers. 

6.3 In Situ Rock Testing 

In situ stress conditions of rocks are used in finite element analyses, estimating loading on tunnels, 

determining rock burst susceptibility in excavations, and identifying regional active and residual stresses. 

Stresses occur as a result of gravity forces, actively applied geologic forces such as regional tectonics, 

and from stored residual-strain energy. Stress is measured to determine the effect on foundations from 

changes in loading brought about by excavation or construction. Where confinement of a material has 

been removed by natural means or by excavation, the remaining material tends to approach a residual 

state of stress. In a majority of projects, the major principal stress is vertical, i.e., the weight of the 

overlying material. However, it has been found from measurements made throughout the world that 

horizontal stresses in the near surface area, defined as 100 feet (30.48 m) or less, can be 1.5 to 3 times 

higher than the vertical stress. Recognition of this condition during the design phase of investigations is 

very critical. Where high horizontal stresses occur at a project site, the stability of cut slopes and tunnel 

excavations is affected. In situ testing is the most reliable method for obtaining the magnitude and 

direction of stresses. The three most common methods for determining in situ stresses are the 

overcoring, hydrofracture, and flatjack techniques. Table 8 lists the field tests that can be used to 

determine in situ stress conditions.

69 NUREG/CR-5738
6. In Situ Physical Testing

Table 8 In Situ Tests to Determine Stress Conditions 

Department of the Army, 1984)

(adapted from EM 1110-1-1804,

Bibliographic 

Test Soils Rocks Reference Remarks 

Hydraulic fracturing X Leach (1977) Only for normally consolidated or slightly 

Mitchell et al. (1978) consolidated soils 

Hydraulic fracturing X RTHa 344 Stress measurements in deep holes for 

Goodman (1981) tunnels 

Hamisen (1978) 

Vane shear X Blight (1974) Only for recently compacted clays, silts 

and fine sands (see Blight, 1974, for 

details and limitations) 

Overcoring X RTH 341-80 Usually limited to shallow depth in rock 

techniques Goodman (1981) 

Rocha (1970) 

Flatjacks X Deklotz and Boisen (1970) 

Goodman (1981) 

Uniaxial X X RTH 365-80 May be useful for measuring lateral 

(tunnel) jacking stresses in clay shales and rocks, 

also in soils 

a Rock Testing Handbook.

NUREG/CR-5738 70
6. In Situ Physical Testing

6.3.1 Residual Stress 

6.3.1.1 Overcoring Method. Possibly the most common method used for measuring in situ stresses in 

rock for depths up to 150 feet or less is overcoring. An NW (3-1/2-inch diameter) core hole is drilled, 

instrumented with strain gages, and redrilled with a larger core barrel. The overcoring decouples the 

rock surrounding the instrument package from the natural stress field of the in-place formation. The 

change in strain is then converted to stress by using the elastic modulus of the intact rock determined 

from laboratory tests. At least three separate tests must be made in the rock mass in nonparallel 

boreholes. A detailed description of the field test is given in the Rock Testing Handbook (RTH 341-80, 

"Determination of In Situ Stress by the Overcoring Technique," DA, 1993). The overcoring method is 

hampered by the presence of numerous instrument lead wires, which may be broken during testing. The 

practical maximum depth of testing is usually less than 150 feet. The three-component borehole 

deformation gauge method (Hooker and Bickel, 1974) is described in detail in the RTH 341-80. 

6.3.1.2 Photoelastic Inclusion Method. Another approach is the photoelastic inclusion method. A 

photoelastic inclusion permits the measurement of the maximum and minimum stresses in the plane 

normal to the drillhole axis. This method is relatively inexpensive but can be complicated or erratic if 

rock anisotrop) and deformations caused by fine material are not considered. The photoelastic inclusion 

method is described in the RTH 342-89, "Suggested Method for Determining Stress by a Photoelastic 

Inclusion." (DA. 1993). 

6.3.1.3 Flatjack Method. In the flatjack method, two points are inscribed on the rock walls of a tunnel. 

A slot is bored or cut into the rock wall midway between the inscribed points. Stresses present in the 

rock will tend to partially close the slot. A hydraulic flatjack is then inserted in the slot, and the rock is 

jacked back to its onginal position as determined by the inscribed points. The unit pressure required is a 

measure of the in situ stress. The value recorded must be corrected for the influence of the tunnel 

excavation itself. Flatjack tests obviously need an excavation or tunnel for the test. The high cost for 

constructing the opening usually precludes this technique as an indexing tool except where the size of the 

structure and complexity of the site dictate its use. The flatjack tests can also be used as deformation 

tests and due to their versatility and size, can be adapted to a number of configurations. However, the 

jack tests only a small volume of rock, making it difficult to calculate deformation or failure properties. 

6.3.1.4 Hydrofracture Method. The hydrofracture method has been used in soils and rock and 

theoretically has no depth limitation, even though it loses accuracy after 100 ft or more. To conduct the 

test, a section of hole is isolated with packers at depth and an increasingly higher water pressure applied 

to the section. A point will be reached where the water pressure begins to level off, and there is a marked 

increase in water take. This indicates that a crack in the formation has opened, and the threshold 

pressure has been reached. The threshold pressure measures the minor principal stress component. The 

orientation of the crack is then obtained by an impression packer. This procedure then gives the 

intensity and direction of the minor principal stress, which is perpendicular to the crack. The 

hydrofracture method has no particular depth limitation, but drilling deep holes can be very expensive. 

This expense can often be circumvented by using holes that have been drilled for other purposes. 

Evidence indicates that stresses measured within 100 feet or more of the ground surface may not always 

reflect the actual stress magnitude or orientation at depth. This may be true particularly in areas where 

closely jointed and weathered surface rock formations are decoupled from the deeper, more intact rock.

71 NUREG/CR-5738
6. In Situ Physical Testing

6.3.2 In situ Deformability Tests 

Deformation characteristics of subsurface materials are of major importance in dynamic and seismic 

analyses for dams and other large structures, static design of concrete gravity and arch dams, tunnels, and 

certain military projects. Geotechnical investigations for such purposes should be planned jointly by 

geotechnical and structural engineers. Deformation properties are normally expressed in terms of three 

interdependent parameters: Young's modulus, shear modulus, and Poisson's ratio. These parameters 

assume that materials are linear elastic, homogeneous, and isotropic. In spite of this limitation, these 

parameters are often used to describe the deformation properties of soil and rock. Large-scale tests (e.g., 

tunnel jacking) are frequently used because they reduce the effect of non-homogeneity. Multiple tests, 

with different orientations, can be used to determine the anisotropy of the deformation properties. Soils, 

in particular, tend to be nonlinear and inelastic. As a result, their properties are often strain dependent, 

i.e., moduli determined at low strain levels can be substantially different from those determined at high 

strain levels. 

The fact that sample disturbance, particularly in soils, can substantially affect the deformation properties 

serves as the primary reason for using in situ tests in soils. Table 8 lists the in situ tests used to determine 

one or more of the deformation parameters. Some test results are difficult to relate to the fundamental 

parameters but are used directly in empirical relationships (Table 9). Deformation properties of a jointed 

rock mass are very important if highly concentrated loadings are anticipated and tolerance for 

displacement under final loading is low. One problem often encountered in conducting in situ 

deformation tests is the need to include representative sizes of the jointed rock mass in the test, 

particularly if the joint spacing is moderately large (e.g., 2 to 3 feet). This problem has been solved in 

some instances by excavating a chamber in rock, lining it with an impermeable membrane, and subjecting 

it to hydraulic pressure to load the rock over relatively large areas. 

6.3.2.1 Chamber Tests. One of the limitations of in situ deformation testing for jointed rock masses is 

the necessity of representative sizes. Chamber tests can be performed to overcome this problem. This 

test determines the deformability of a rock mass by subjecting the cylindrical wall of a tunnel or chamber 

to hydraulic pressure and measuring the resultant rock displacements. With this data, the elastic or 

deformation moduli are calculated (RTH 361-89, "Suggested Method for Determining Rock Mass 

Deformability Using a Pressure Chamber," DA, 1993). Chamber tests are performed in large 

underground openings. Generally these openings are test excavations such as exploratory tunnels. 

Pre-existing openings, such as caves or mine chambers, can be used if available and applicable to project 

conditions, or a chamber may be excavated in the rock for this purpose. The opening is lined with an 

impermeable membrane and subjected to hydraulic pressure. Instrumented diametrical gages are used to 

record increases in tunnel diameter as the pressure load increases. The test is performed through several 

load-unload cycles. The data are subsequently analyzed to develop load-deformation curves from which 

a deformation modulus can be computed. 

6.3.2.2 Uniaxial Jacking Test. An alternative to the chamber tests is the tunnel, or uniaxial jacking test 

(Rock Testing Handbook, RTH 365-80). This test uses a set of diametrically opposed jacks to test large 

zones of rock in the radial direction from the axis of the tunnel. This method produces nearly 

comparable results with chamber tests without incurring the much greater expense. The test determines 

how foundation rock will react to controlled loading and unloading cycles and provides data on 

deformation moduli, creep, and rebound. The jacking test is the preferred method for determining 

deformation properties of rock masses for large projects. It is a more economical alternative to the 

chamber tests with comparable results (Figure 10). Information on site selection, preparation of test site,

NUREG/CR-5738 72
6. In Situ Physical Testing

Table 9 In Situ Tests to Determine Deformation Characteristics (adapted from 

EM 1110-1-1804, Department of the Army, 1984) 

For 

Test Soils Rocks Reference Remarks 

Geophysical X X EM 1110-1-1802 For determining dynamic Young's Modulus, E, 

refraction, cross- at the small strain induced by test procedure. 

hole and downhole Test values for E must be reduced to values 

corresponding to strain levels induced by 

structure or seismic loads 

Pressuremeter X X RTHa 362-89 Baguelin, et al. Consider test as possibly useful but not fully 

(1972), Mitchell et al. (1978) evaluated. For soils and soft rocks, shales, 

etc. 

Chamber test X X Hall et al. (1974) 

Stagg and Zienkiewicz (1968) 

Uniaxial (tunnel) X X RTH 365-80 

jacking Stagg and Zienkiewicz (1968) 

Flatjacking X Deklotz and Boisen (1970) 

Goodman (1981) 

Borehole jack X RTH 363-89 

or dilatometer Stagg and Zienkiewicz (1968) 

Plate bearing X RTH 364-89 

Stagg and Zienkiewicz (1968) 

Plate bearing X MIL-STD 621 A, Method 104 

Standard X Hall et al. (1974) Correlation with static or effective shear 

penetration modulus, in psi, of sands; settlement of 

footings on clay. Static shear modulus of 

sand is approximately: G., = 1960N°-' in 

psi; N is SPT value 

a Rock Testing Handbook.

NUREG/CR-5738 73
Figure 10. Uniaxial jacking test. (RTH)

C) 

00

ON 

C,) 

C 

H 

C,)
6. In Situ Physical Testing

equipment installation, testing and removal can be obtained in the RTH 365-80, "Bureau of Reclamation 

Procedures for Conducting Uniaxial Jacking Tests," (DA, 1993). 

6.3.2.3 In Situ Uniaxial Compressive Test. This test is used to measure strength and deformability of 

large, in situ specimens of weak rocks such as coal. The strength of the rock mass depends on the sample 

size, so to find the value of engineering significance, samples of increasing size are tested until an 

asymptotic constant strength value is obtained (Bieniawski and Van Heerden, 1975). A block specimen 

is cut from the site to be tested and loaded until failure occurs. Preferably, a deformation-controlled 

loading system should be used. Details in testing arrangements, preparation, and calculations procedures 

are described in the RTH 324-80, "Suggested Method for Deformability and Strength Determination 

Using an In Situ Uniaxial Compressive Test." 

6.3.2.4 Other Deformation Tests. Other methods for measuring deformation properties of in situ rock 

are anchored cable pull tests, flatjack tests, borehole jacking tests and tunnel jacking tests. The anchored 

cable pull test uses cables, anchored at depth in boreholes, to provide a reaction to large slabs or beams 

on the surface of the rock. The test is expensive and difficult to define mathematically, but offers the 

advantages of reduced shearing strains and larger volumes of rock being incorporated in the test. 

Flatjack tests are flexible and numerous configurations may be adopted. In relation to other deformation 

tests, the flatjack test is relatively inexpensive and useful where direct access is available to the rock face. 

Limitations to the method involve the relatively small volume of rock tested and difficulty in defining a 

model for calculation of deformation or failure parameters. The borehole jack ("Goodman" jack) or 

dilatometer has the primary advantage that direct access to the rock face is not required. The 

development of a mathematical model for the methods, however, has proven to be more difficult than 

with most deformation measurement techniques. 

Radial tunnel jacking tests are similar in principle to the borehole jacking tests except that larger volumes 

of rock are involved in the testing. Typically, steel rings are placed within a tunnel with flatjacks placed 

between the rings and the tunnel surfaces. The tunnel is loaded radially and deformations are measured. 

The method is expensive but useful, and is in the same category as chamber tests. The small downhole 

plate-loading tests (Wrench, 1984) can also be used to determine deformability characteristics of a rock 

mass. The test is performed by loading a flat surface at the end of a drill hole or other recess and 

measuring the resultant displacement of that surface. Elastic or deformation moduli are calculated, as 

well as time dependent (creep) properties (RTH 364-89, "Method for Determining Rock Mass 

Deformability by Loading a Recessed Circular Plate"). (Figures 11 and 12). 

Pressuremeter tests in soft rock for deformability consist of lowering an inflatable cylindrical probe into 

a predrilled borehole, expanding the probe laterally against the borehole wall, and recording the increase 

in size of the probe and associated pressure within the probe (RTH 362-89, "Pressuremeter Tests in Soft 

Rock"). The test can be performed at any desired depth and is terminated if yielding in the rock becomes 

large. From the recorded data, a pressure-volume curve is plotted and a pressuremeter modulus is 

calculated. The calibration of the probe, procedures, and calculations are described in RTH 362-89. 

The point load strength test is a field or laboratory test for intact strength, an index test for strength 

classification of rock material. The test can be performed either in the laboratory or in the field with 

portable equipment, using core samples (diametral and axial tests), cut blocks (block tests), or irregular 

lumps (irregular lump test) (Haramy, Morgan, and De Waele, 1981). The test consists of a loading 

system, a loading measuring system, and a distance measuring system. Details of specimen selection, 

preparation, equipment calibration, and the different tests is available in the RTH 325-89.

75 NUREG/CR-5738
Figure 11. Plate-loading equipment. (RTH)

z 

C., 

LA 

ON

ON 

cj3 

r-e 

0< 

HD 

Ci

IS-- OF PLASIFA
6. In Situ Physical Testing

Figure 12. Details of plate tests equipment. (RTH)

77 NUREG/CR-573 8
7. Handling, Field Storage, and Transportation of Samples

6.3.3 Determination of Dynamic Moduli by Seismic Methods 

Seismic methods, both downhole and surface, are used on occasion to determine in-place moduli of rock. 

The compressional wave velocity is mathematically combined with the rock's mass density to estimate a 

dynamic Young's modulus, and the shear wave velocity is similarly used to estimate the dynamic rigidity 

modulus. However, because rock particle displacement is so small and loading transitory during these 

seismic tests, the resulting modulus values tend to be too high. The seismic method of measuring rock 

modulus should not be used in cases where a reliable static modulus value can be obtained. Even where 

the dynamic modulus is to be used for earthquake analysis, the modulus derived from seismic methods is 

too high. The moduli and damping characteristics of rock are strain dependent, and the strains imposed 

on the rock during seismic testing are several orders of magnitude lower than those imposed by a 

significant earthquake. Generally, as the strain levels increase, the shear modulus and Young's modulus 

decrease and the damping increases. Consideration of these factors is necessary for earthquake analysis. 

7 HANDLING, FIELD STORAGE, AND TRANSPORTATION OF 

SAMPLES 

The handling, storage and transportation of samples are as critical for sample quality as the collecting 

procedures. Disturbance of samples after collection can happen in a variety of ways and transform 

samples from high quality, to slightly disturbed, to completely worthless. Soil samples can change 

dramatically due to moisture loss, moisture migration within the sample, freezing, vibration, shock, or 

chemical reactions. 

Moisture loss may not be critical on representative examples, but it is preferable that it is kept to a 

minimum. Moisture migration within a sample provokes differential residual pore pressures to equalize 

with time. Water can move from one formation to another causing significant changes in the undrained 

strength and compressibility of the sample. Freezing of clay or silt samples can cause ice lenses to form 

and dramatically disturb the samples. Storage room temperatures for these kinds of samples should be 

kept above 4 deg C. Vibration or shock can provoke remolding, changes of strength, or density changes, 

specially in soft and sensitive clays or cohesionless samples. Transportation arrangements to avoid these 

effects need to be carefully designed. Chemical reactions between samples and samples container can 

occur during storage time and can provoke changes that can affect soil plasticity, compressibility, or 

shear strength characteristics. The correct selection of sample container material is important. 

Cohesionless soil samples are particularly sensitive to disturbance due to impact and vibration during 

removal from borehole, from sampler and subsequent handling. Samples should be kept in the same 

orientation as that in which they were sampled at all times (e.g. vertical position if sampled in a vertical 

borehole), well padded for isolation from vibration and impact, and transported with extreme care if 

undisturbed samples are required. 

7.1 Undisturbed Samples 

Undisturbed samples must be handled and preserved in a manner to preserve stratification or structure, 

water content, and in situ stresses, to the extent possible (EM 1110-1-1906, DA, 1996). Once the 

material is brought to the surface, the sample itself should be sealed in a container or the soil sample 

removed from the sampler and sealed in an appropriate transporting container. If the sample will be

NUREG/CR-5738 78
7. Handling, Field Storage, and Transportation of Samples

stored in the containers for a period of time, precautions should be taken against chemical reactions 

between the sample and the container. Samples collected for water content information should be sealed 

to avoid soil moisture changes, and if glass jars are used, a good seal should be assured between the 

sealing edge and the cap. Guidance for handling, transportation, and preservation of samples can be 

obtained from EM 1110-1-1906 (DA, 1996), and ASTM D 4220-95, "Standard Practices for Preserving 

and Transporting Soil Samples." 

7.1.1 Block Samples 

Block samples need to be protected from moisture loss. The sample should be sealed by brushing with 

paraffin to develop a 2 mm coating, then wrapped in cheesecloth or clinging plastic wrap, and dipped 

again in paraffin to develop a 4 mm covering. If the specimen is too big for dipping it can be put in an 

oversized box and paraffin or polyurethane foam is poured on the sample to encase it. Wax seals can 

become ineffective after a few months and cracks may appear. Storage conditions should be kept cool 

and humid to minimize moisture loss after wax imperfections appear (Figure 13). 

7.1.2 Sample Storage in Tubes 

Using a cup cleanout auger, 5 cm (2 inches) of the material at the bottom of the sampling tube should be 

removed to be replaced with an expandable packer to seal the sample. The material removed from the 

tube should be stored in an appropriate container to be used for classification or water content 

determination afterwards. 

7.1.2.1 Cohesionless Soils. Tubes containing cohesionless soils should be sealed with paper towel and a 

perforated expandable packer inserted at the bottom of the sampling tube. Once the sample is removed 

from the sampling apparatus, a cup cleanout auger should be used to remove the cuttings at the top. A 

metal disk (e.g., the bottom half of an expandable packer) is then placed on the top surface of the sample. 

The tube is subsequently kept in a vertical upward position. In this manner, any changes in the distance 

from the top of the tube to the metal disk would indicate that the sample has suffered changes in volume. 

Thus the distance should be measured immediately after cleanup of the top of the sample, at intermediate 

stages, and before the sample is extruded for testing. 

The sample must be placed in a rack to drain. After drainage, the tube should be sealed with an 

expandable packer and filter paper. The excess moisture from the sample will be drained through the 

paper without losing sample material, minimizing sample handling disturbance and preventing 

liquefaction. The sample should never be allowed to dry completely since then it would be impossible to 

subsample. 

Cohesionless sands with low content of fines and without fine material lenses can be frozen in the 

sampling tube and transported in this way, minimize transportation and handling disturbances 

(Figure 14). The sample should be drained prior to freezing to prevent structural changes due to water 

expansion. 

7.1.2.2 Cohesive Soils. Undisturbed samples of cohesive soils can be removed from the sampling tube 

as they are collected, but if they are going to be preserved in the sampling tube, some material at the 

bottom and the top of the sampling tube should be removed. The cuttings at the top should be 

documented and measured, the material from the bottom of the tube should be appropriately stored, and 

the tube sample sealed with solid, impermeable packers.

79 NUREG/CR-5738
7. Handling, Field Storage, and Transportation of Samples

(a) Level ground surface, mark outline 

of sample and carefully excavate trench

(b) Deepen excavation below base of 

sample. and trim to size with a knife

Two additional layers of cheese cloth and warm 

wax are required to seal the sample

One thickness of cheese cloth is placed 

against soil, followed by an application 

of warm wax, rubbed by hand

fill space between sample and box, 

to provide support 

(d) Encase sample in a wooden box, 

packed with foam or damp 

woodshavings, if soil is easily d~sturbed 

Block sampling in a trial pit.

(c) Seal with three layers of cheese cloth or 

plastic foodwrapping, waxing each layer by 

brush, or hand

(e) Cut sample from bottom of pit, and 

seal base as in (c). Place wooden lid, 

if box is used

Figure 13. Block sampling (Clayton, Matthews, and Simons, 1995; reprinted with permission).

NUREG/CR-573 8 80
7. Handling, Field Storage, and Transportation of Samples

Fig. 4. Evolution of temperature profile in a sample 

during freezing. 

Temperature (°C) -80.0 -60.0 -40.0 -20.0 0.0 

50 -----

S40 

,35 , t --- " , 

. 30 1 

S20 

S00

Top plate fixed 

to sampling tube 

Saturated 

base plate

Gradual removal of 

insulation as freezing 

progresses

20.0

Figure 14. Procedure for freezing of samples (Konrad, St. Laurent, Gilbert, and Leroueil, 1995; 

reprinted with permission).

NUREG/CR-5738

(o) I

Thermistance

81
7. Handling, Field Storage, and Transportation of Samples

7.1.3 Sample Removal 

7.1.3.1 Cohesionless Soils. In situ densities can be measured in the field from undisturbed cohesionless 

samples by removing soil from the tube in increments with a cup cleanout auger and measuring the 

volume and weight of the soil for each increment. Any material that adheres to the tube sides should be 

removed with a sampling tube wall scraper and included with the respective soil increment. The portion 

of soil remaining in a sampling tube may be extruded as discussed below for cohesive soils; freezing will 

ensure that disturbance of structure is very slight. 

7.1.3.2 Cohesive Soils. Undisturbed samples of cohesive soils to be removed from the sampling tube 

should be extruded as soon as possible to minimize adhesion and friction development between the 

sample and the sampling tube. The sample should be pushed out of the sampler in the same direction that 

it was sampled, in a single, smooth, uniform stroke. This may be accomplished using a hydraulic 

extruding piston at the bottom of the sample that has been previously trimmed. Hydraulic jacks are the 

preferred method for extruding soil samples; since pneumatic jacks are not acceptable and mechanical 

jacks are used only if hydraulic pressure is not available. 

The sample should be extruded into half-section receiving tubes of the same diameter as the sampling 

tube, to permit the sample to be examined for classification and stratification and preserved to be 

transported to the laboratory. This process has to be done as quickly as possible to reduce moisture loss 

and keep disturbances to a minimum. To preserve the sample, it should be placed in a wax-coated 

cardboard tube of about 25 mm (1 inch) larger than the sample and coated with a wax mixture 

(1:1 mixture of paraffin and microcrystalline wax) at a temperature of less than 10 deg C (18 deg F) so it 

will not penetrate the soil and thus limiting the usefulness of the sample. The sample should be centered 

in the tube and the space between the tube and the sample filled with wax, including the top. The sample 

should not be wrapped with foil or plastic. If it is too fragile for handling, cheese cloth can be used to 

reinforce the sample for handling. 

7.1.4 Sample Transportation 

Undisturbed sample tubes should be packed in the appropriate orientation (as sampled originally) in 

prefabricated shipping containers or in moist sawdust or similar packing materials to reduce the 

disturbance due to handling and shipping. Soil samples should be protected from temperature extremes 

and exposure to moisture (EM 1110-1-1906, DA, 1996). Guidance for handling, transportation, and 

preservation of samples can be obtained from ASTM D 4220-95. 

7.2 Disturbed Samples 

Disturbed samples can be taken for moisture content and determination of plasticity characteristics in the 

laboratory, or for determination of in situ density. The samples can be sealed into watertight containers 

and transported by any convenient means and should be clearly labeled inside and outside of the box 

with: site identification, boring number, sample interval, length of sample lost or not recovered in each 

sample interval, and top and bottom depth of sample interval. 

Rock cores should be stored and transported in durable boxes with dividers to avoid shifting of cores in 

any direction. Special containers may be needed for samples for fluid content determinations or to 

prevent changes in mechanical properties in shales that would be caused by changes in moisture content.

NUREG/CR-5738 82
References

7.3 Care and Storage 

Exploratory or other cores, regardless of age, should be retained until the detailed logs, photographs, and 

test data have been made a matter of permanent record. Precautions should be taken to insure against the 

disposal, destruction, or loss of cores that may have a bearing on any unsettled claim. Such cores should 

be retained until final settlement of all obligations and claims. 

7.4 Disposal 

Soil samples may be discarded once the testing program for which they were taken is complete and as 

the responsible party decides. Soil samples are not normally retained for long periods because even the 

most careful sealing and storing procedures cannot prevent the physical and chemical changes that, in 

time, would invalidate any subsequent test results. 

All exploratory and other cores not used for test purposes should be properly preserved, boxed, and 

stored in a protected storage facility until disposal. The following procedures govern the ultimate 

disposition of the cores in accordance with ER 1110-1-1803 and are presented as an example protocol: 

"Cores over 6 inches in diameter may be discarded after they have served their purpose. In a case 

where the project is deauthorized, all associated cores may be discarded. When a project has been 

completed and final settlement has been made with the contractors and others concerned, all cores, 

except those related to future construction, and a few selected cores representative of foundation and 

abutment conditions, may be discarded. Selected cores, retained after the completion of a project, 

and additions thereto, may be discarded or otherwise disposed of 5 years after final completion of the 

project, provided no unforeseen foundation or abutment conditions have developed. After cores are 

disposed of, core boxes should be salvaged for reuse if their condition and previous use permits it." 

7.5 Low-Level Radioactive Waste and Mixed Waste 

Regulatory and management responsibilities for low-level radioactive waste and mixed waste, are 

defined/enforced by federal agencies such as the Nuclear Regulatory Commission (NRC), the 

Department of Energy (DOE), Environmental Protection Agency (EPA), the Department of 

Transportation (DOT), and the Occupational Safety And Health Administration (OSHA). Background 

guidance for regulatory and management responsibilities for Army users, for low-level radioactive waste 

and mixed waste are specified in EM 1110-35-1, as an example. Specific technical and engineering 

guidance to personnel for the collection, handling, treatment, and disposal of these wastes for Army 

users, is available in EM 1110-1-4002. 

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D 420 - D 4914, ASTM 100 Barr Harbor Drive, West Conshohocken, PA.

NUREG/CR-5738 83
References

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Vicksburg, MS, 1982.

NUREG/CR-5738 84
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In Situ Stress by Means of Large Flatjacks," Determination of In Situ Modulus of Deformation of Rock, 

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Douglas, B.J.. and R.S. Olsen, "Soil Classification Using the Electric Cone Penetrometer," Proceedings 

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NUREG/CR-5738 86
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91 NUREG/CR-5738
Appendix A Geologic Mapping Procedures Open Excavations

APPENDIX A 

GEOLOGIC MAPPING PROCEDURES 

OPEN EXCAVATIONS 

A-1. Purpose of Excavation Mapping. 

a. The primary purpose of the excavation map and/or foundation geologic map is to provide a 

permanent record of conditions during excavation. This permanent record will assist in making the most 

equitable contract adjustments, provide otherwise unattainable information for use in diagnosing post

construction problems and in planning remedial action, and allow for a better interpretation of post

construction foundation instrumentation data. An important prelude to performing geologic mapping of 

the final foundation and/or excavation is monitoring conditions during excavation. Monitoring 

conditions during excavation provides the basis for discovering, at the earliest possible moment, those 

adverse conditions (differing from original predictions) that may cause expensive design modifications 

and construction delays. Foundation and other excavation surfaces should not be covered until mapping 

is complete and approved by project geologist of geotechnical engineer. 

b. A plan for monitoring also provides a basis for installing appropriate instrumentation and 

interpreting foundation instrumentation data as the excavation proceeds. The Instrumentation Data 

Package (Woodward-Clyde, in press), a PC-based program that can store, retrieve, and graphically 

present instrumentation data related to construction monitoring, will soon be available through the U.S. 

Army Engineer Research and Development Center World Wide Web site. 

A-2. Possible Adverse Conditions. 

a. Adverse conditions can affect the stability of excavated slopes during construction, stability of 

permanent slopes, foundation settlement, foundation bearing capacity, sliding stability of structures, and 

planned water control measures such as grouting and drainage requirements. Such conditions can occur 

in both soil and rock. Features of engineering significance in both soil and rock frequently occur in 

geometrically predictable patterns. The prediction of geometry is enhanced by knowledge of the local 

geologic history. 

b. Adverse conditions that occur in soils include soft compressible zones of clay or organic 

materials; lateral compositional changes related to variations in depositional environment; changes in the 

relative density of granular materials; fill containing trash or other undesirable materials; swelling or 

slaking in hard, fissured clays; and changes in permeability. 

c. Adverse conditions that can occur in rocks include weathering, soft interbeds in sedimentary and 

volcanic rocks, lateral changes, presence of materials susceptible to volume change (e.g., swelling clay 

shales, sulfide-rich shales, gypsum, and anhydrite), adversely oriented fractures (e.g., joints, bedding 

planes, schistosity planes, and shear planes), highly fractured zones, and fault, joints, shear planes filled 

with soft materials, or exceptionally hard layers that inhibit excavation method or grout/drain hole 

drilling. 

d. Adverse conditions related to groundwater include unexpectedly high cleft or pore pressures 

which reduce effective stress, swelling materials, slaking, piping, sand runs, and uplift pressures on 

partially completed structures. It should be noted that most water-induced problems stem from 

unanticipated changes in the groundwater regime.

A-1I NUREG/CR-5738
Appendix A Geologic Mapping Procedures Open Excavations

A-3. Monitoring and Mapping Procedures. 

a. The difference between excavation monitoring and record mapping is small; both involve the 

observation and reporting of natural conditions. The need for monitoring the condition of slopes during 

construction include safety during construction and the prediction of conditions at grade. Potential 

problem areas can be detected and avoided, or corrective treatment can be started before a problem be

comes severe. 

b. Depending on the speed of excavation, monitoring should be performed on a daily, biweekly, or 

weekly basis. Because of increasing steepness, rock slopes become less and less accessible as excavation 

progresses. Table A-l is an excavation monitoring checklist, which, if followed should insure adequate 

coverage. Geologic sections can be constructed to assist in predicting the locations of features at grade. 

While many geologic features are arcuate or sinuous, many are planar. The location of a planar feature at 

grade can be found by graphic projection or by calculation as shown on Figure A-1. 

c. Excavation and foundation mapping are generally performed on an intermittent and 

noninterference basis. If advantage is not taken of every mapping opportunity, the rock surface may be 

covered before another opportunity occurs or the contractor may be subjected to undue delay. 

Furthermore, systematic mapping makes for better monitoring. Thoroughness of mapping, type of 

mapping procedure, and sequence in which it is accomplished are functions of the purpose for which the 

mapping is required and of the construction schedule. 

d. A number of items should be done to prepare for mapping before the excavation is started. 

(1) The geologist with mapping responsibility should make an interpretation, or confirm the existing 

interpretation of the geologic conditions (a geologic model). He should decide on a mapping strategy and 

prepare field base map sheets. The map scale is partially dependent on the amount of detail to be 

mapped. If the excavation will be in hard, fractured rock, a field scale of 1 in. = 5 ft. and a final 

compiled map scale of 1 in. = 10 ft. would be suitable. If the excavated material is a soil, a soft lightly 

fractured sedimentary rock, or a glacial till, field and compiled scales of I in. = 10 ft. and 1 in. = 50 ft. 

could be suitable. The field base maps should have reference lines for location purposes. In structure 

foundation areas, the structure outline will be enclosed by concrete forms that are easily locatable, 

making handy reference lines. The location of features inside reference lines can be facilitated by use of 

cloth tape grids, or with differential GPS. 

(2) Decide at what intervals to map as the excavation progresses. Mapping intervals will be affected 

by a number of factors including the rate of excavation, lift thicknesses, and the need for temporary slope 

protection. In most cases, the mapping should be done in the plane of slopes; projection to other planes 

can be made after the mapping is completed. An exception occurs if mapping is done with a plane table. 

In this case, a horizontal reference plane is required. Camera positions should be selected for sequential 

photographs during excavation. Reference lines for mapping can be provided by stretching tapes from 

the top to bottom of the slope at 10- to 20-ft intervals. Final excavation topographic maps should be 

made that can be used as a base for the geologic map. 

(3) Determine whether the side slopes will be too steep for unassisted access. Temporary soil slopes 

usually range from IV on 3H to IV on IH. Temporary rock slopes usually range from IV on 1H to 

vertical. It is not possible to walk slopes steeper than 1V on 1-1/2H unless they are very irregular. Thus, 

safety lines will be needed on most rock slopes and on some soil slopes.

NUREG/CR-5738 A-2
Appendix A Geologic Mapping Procedures Open Excavations 

Table A-1 

Suggested Geologic Excavation Monitoring Checklist 

Project 

Excavation For Structure 

Period: To 

1. Excavation Progress: 

a. Type Excavation: (common or rock) 

b. Location: Sta To Offset 

2. Rock or soil type: 

3. Rock or soil conditions: (hardness, stiffness, weathering, fracturing, sloughing, etc.) 

4. Water inflow, locations and gpm: 

5. Significant features or defects: (those which may cause problems (andlor may extend to grade) 

6. Slope protection: (protection or reinforcement, location, type thickness, etc.) 

7. Blasting conditions: (presplittino locations and successes, production blasting, powder factor, hole spacing, delay 

patterns, deviations from approved rounds, fragment size, overbreak, etc.) 

8. Ripping conditions: (single or multitooth, drawbar horsepower, easy or hard, disturbance below grade or slopes) 

9. Additional remarks: (unusual incidents, accidents, explorations, etc.) 

10. Mapping progress: 

a. Location 

b. Adequacy of coverage (rock surface clean?, percent obscured by slope protection?. etc.) 

c. Photos taken: (where, or what) 

11. Instrumentation installed: 

a. Location 

b. Type and amount 

12. Instrumentation read: 

a. Location 

b. Type 

A-3 NUIREG/CR-5738
Appendix A Geologic Mapping Procedures Open Excavations

B tan - Sin sdand 

t Fan 0 or 

~H a sin - -i )•tn where: 

a acute angle between strike of planar 

feature and section 

.tru dip of planar feature 

:= acute angle of excavation slope 

B distance, in section, from toe of 

excavation slope to outcrop at 

excavation grade 

d - distance, at section, from toe of 

excavation slope to surface outcrop 

of feature 0 

D = depth of excavation 

H = height in section of feature outcrop 

above grade 

Figure A-i. Excavation plan and sections showing intersecting planar feature.

NUREG/CR-5738 A-4
Appendix A Geologic Mapping Procedures Open Excavations

(4) Where the slopes are nearly vertical, consideration can be given to mapping on large-scale 

photographs. However, there must be time to produce the photographs for use as a map base. 

e. It is desirable to have a contract provision for interim rock surface cleanup. The final foundation 

cleanup item will suffice for mapping purposes at final grade. However, the need may arise for detailed 

examination of particular areas during excavation. Excavation slopes may need sealing or other interim 

protection against weathering. 

f. During mapping, complete descriptions of all geologic features should be made (e.g., rock types, 

bedding, fracturing, joints, shear zones, etc.). All features, geologic and otherwise (including ledges and 

breaks in slope) should be located and drawn on the base map. Table A-2 provides descriptive criteria 

for use during mapping. Insofar as possible, the information on Table A-2 is consistent with information 

provided in EM 1110-1-1806. 

g. To the maximum extent possible, USGS map symbols or variations of these symbols should be 

used. In most cases, the geologist should represent geologic features by showing the trace of the feature 

on the map. The trace will allow a reasonably accurate location of each significant feature. 

h. Frequently, foundation maps and sections are prepared with rock type symbols covering the entire 

area of the particular rock type. However, if all the recognizable distinct geologic features are also 

located on the drawing, it will be cluttered and difficult to read. Thus, the primary purpose of the 

foundation record will be obscured. Each mark on the foundation map should have physical significance. 

Figure A-2 depicts the foundation for the cutoff trench in sedimentary rocks beneath an earth dam. 

i. Records should be made of foundation treatment, such as grout hole locations, dental work, 

pneumatic concrete, rock-bolt locations, and wire mesh. Portrayal of such treatment can be included on 

the geologic map. However, if the resulting map is too cluttered, either the treatment should be portrayed 

in a series of transparent overlays, or the scale of the mapping should be enlarged. A GIS is ideal for 

subdividing the geotechnical (and other construction) information into a series of data layers which can 

be digitally overlaid. In a GIS, map scales can be easily altered, and adjustments of the geotechnical 

information can be readily accomplished for presentation in a comprehensible format. 

j. The importance of adequate photography and videos of the excavation process and the final slope 

and foundation conditions cannot be overemphasized. Complete video and photographic coverage is as 

important as the foundation maps. All are required for an accurate and complete record of encountered 

conditions. Photographs and videos can be readily incorporated into a GIS. 

k. The photographic coverage should include unobstructed, medium-scale photographs of the entire 

foundation and closeup views of significant geologic features; a photograph through a mat of reinforcing 

steel is useless. All photographs should be annotated by the geologist and clearly sited on a photograph 

location map.

A-5 NUREG/CR-5738
Appendix A Geologic Mapping Procedures Open Excavations 

Table A-2 

Descriptive Criteria, Excavation Mapping 

I. Rock Type. 

a. Rock Name (Generic). 

b. Hardness. 

(1) Very soft: can be deformed by hand. 

(2) Soft: can be scratched with a fingernail. 

(3) Moderately hard: can be scratched easily with a knife. 

14) Hard: can be scratched with difficulty with a knife. 

(5) Very hard: cannot be scratched with a knife. 

c. Degree of Weathering. 

(1) Unweathered: no evidence of any mechanical or chemical alteration. 

(2) Slightly weathered: slight discoloration on surface, slight alteration along discontinuities, less than 10 percent 

of the rock volume altered, and strength substantially unaffected. 

(3) Moderately weathered: discoloring evident, surface pitted and altered with alteration penetrating well below 

rock surfaces, weathering "halos" evident; 10 to 50 percent of the rock altered, and strength noticeably less 

than fresh rock. 

(4) Highly weathered: entire mass discolored, alteration pervading nearly all of the rock with some pockets of 

slightly weathered rock noticeable, some minerals leached away, and only a fraction of original strength 

retained (with wet strength usually lower than dry strength). 

(5) Decomposed: rock reduced to a soil with relict rock texture Isaprolite), and generally molded and crumbed by 

hand. 

d. Lithology. Macro Description of Mineral Components. Use standard adjectives such as shaly, sandy, silty, and 

calcareous. Note inclusions, concretions, nodules, etc. 

e. Texture and Grain Size. 

(1) Sedimentary rocks: 

Texture Grain Diameter Particle Name Rock Name 

* 80 mm Cobble Conglomerate 

* 5 - 80 mm Gravel 

Coarse grained 2 - 5 mm Medium grained 0.4 - 2 mm Sand Sandstone 

Fine grained 0.1 - 0.4 mm Very fine grained 0.1 mm Clay, silt Shale, claystone, siltstone 

Use clay-sand texture to describe conglomerate matrix. 

(2) Igneous and metamorphic rocks: 

Texture Grain Diameter 

Coarse grained 5 mm 

Medium grained 1 - 5 mm Fine grained 0.1 - 1 mm Aphanite 0.1 mm 

(Continued)

NUREG/CR-573 8 A-6
Appendix A Geologic Mapping Procedures Open Excavations

Table A-2 (Continued) 

(3) Textural adjectives: Use simple standard textural adjectives such as porphyritic, vesicular, pegmatitic, granular, 

and grains well developed, but not sophisticated terms such as holohyaline, hipidiomorphic granular, 

crystalloblastic, and cataclastic. 

2. Rock Structure. 

a. Bedding. 

(1) Massive: 3 ft thick. 

(2) Thick bedded: beds from 1-3 ft thick. 

(3) Medium bedded: beds from 0.3 ft - 1 ft thick. 

(4) Thin bedded: beds less than 0.3 ft thick. 

b. Degree of Fracturing flointing). 

(1) Unfractured: fracture spacing 6 ft. 

(2) Slightly fractured: fracture spacing 3-6 ft. 

(3) Moderately fractured: fracture spacing 1-3 ft. 

(4) Highly fractured: fracture spacing 0.3-1 ft. 

(5) Intensely fractured: fracture spacing 0.3 ft. 

c. Shape of Rock Blocks. 

(1) Blocky: nearly equidimensional. 

(2) Elongated: rodlike. 

(3) Tabular: flat or bladed. 

3. Discontinuities. 

a. Joints. 

(1) Type: bedding, cleavage, foliation, schistosity, and extension. 

(2) Separations: open or closed; how far open. 

(3) Character of surface: smooth or rough; if rough, how much relief; average asperity angle. 

(4) Weathering or clay products between surfaces. 

b. Faults and Shear Zones. 

(1) Single plane or zone: how thick? 

(2) Character of sheared materials in zone. 

(3) Direction of movement, and slickensides. 

(4) Clay fillings. 

c. Solution Cavities and Voids. 

(1) Size. 

(Continued)

A-7 NUREG/CR-5738
Appendix A Geologic Mapping Procedures Open Excavations

Table A-2 (Concluded) 

(2) Shape: planar, irregular, etc. 

(3) Orientation: (if applicable) developed along joints, bedding planes, at intersections of joints and bedding planes, 

etc. 

(4) Filling: percentage of void volume and type and of filling material (e.g., sand, silt, clay, etc.).

NUREG/CR-5738 A-8
Appendix A Geologic Mapping Procedures Open Excavations 

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A-9 NUREG/CR-573 8
Appendix B Geologic Mapping of Tunnels and Shafts

APPENDIX B 

GEOLOGIC MAPPING OF TUNNELS AND SHAFTS 

B-I. Background. 

A method to log all geologic features exposed by underground excavations has been developed by 

U.S. Army Engineer District, Omaha, geologists where all necessary data of a specific geologic 

discontinuity can be recorded at a single point; thus the system may be used in tunnels of almost any 

configuration and inclination. This method is called peripheral geologic mapping. It allows logging of 

all geologic defects regardless of their position on the tunnel walls. Furthermore, this method usually 

will keep pace with modem continuous mining techniques and will immediately provide useful data 

without projecting to plan or profile. Prior to development of this method, the accepted method was to 

project geologic features to a plan placed tangent to a point on the tunnel circumference. Ordinarily such 

tangent points were at springline, wasteline level, or crown. In many instances, geologic features not 

passing through these points were not logged. Further, some systems were useful for logging planar dis

continuities only, such as joints, faults, and bedding planes, as exposed in straight, nearly horizontal 

tunnels of circular cross section. Peripheral geologic mapping uses a developed plan by "unrolling the 

circumference" to form a plan of the entire wall surface. A log of the exposed geology is plotted on this 

plan as mining progresses. Mapping on a developed layout of a cylindrical surface is similar to the 

method used to log the interior of a calyx hole. Actually, a circular tunnel might be visualized as a large 

horizontal or nearly horizontal drill hole. 

B-2. Applications. 

Peripheral geologic mapping may be used to log large-diameter power tunnels and surge tank risers 

(both straight and wye-shaped), vertical shafts, horseshoe-shaped drifts and chambers, and various 

odd-shaped openings on both civil and military projects. It can be used to map a wide range of 

geomaterials from stratified, soft, sedimentary rocks to hard igneous and metamorphic rock masses. The 

method has proved to be simple enough mechanically that technicians can be trained to perform 

round-the-clock mapping under the general supervision of a professional geologist--a necessity where 

several parallel tunnels are driven simultaneously. 

This method is not applicable to TBM driven tunnels with precast liners where mapping may be 

impracticable or impossible. 

B-3. Procedure. 

a. Advance planning is of paramount importance. The developed layouts on which mapping will be 

done should be prepared well in advance. Usually this step in the procedure can be accomplished by 

using the contract plans. A thorough surface and subsurface study of the geology of the immediate area 

is recommended. This study enables the mapper to recognize which geologic features are important and 

readily identify them on the excavation walls. 

b. The map is typically laid out to a scale of 1 in. equals 10 ft. In some instances where 

closely-spaced geologic discontinuities are anticipated, a scale of 1 in. equals 5 ft. should be considered. 

To prepare a mapping plan, draw the crown center line of the tunnel in the center of the plan. Place the 

center line of the invert at both the right- and left-hand edges of the developed layout. The right and left 

springlines of a circular tunnel will be midway between the center line and edges of the plans (Figure 

B-1). Distances down tunnel may be laid out on tunnel stationing. Separate developed plan tracings are

B-1 NUREG/CR-5738
Appendix B Geologic Mapping of Tunnels and Shafts

LiJ 

zV

(L

-J1 0 -- J

0 

C)

(9 

- _z

/ / 

/, /

11

Figure B-1. Preparation of developed plan from a cylindrical cross section. 

NUREG/CR-5738 B-2

H

62 

zL
Appendix B Geologic Mapping of Tunnels and Shafts

typically made for 100-ft lengths of tunnel. For long reaches of equal diameter tunnel, a master tracing 

may be repeatedly printed on a continuous length of paper to cover the entire tunnel length. For 

continuous uninterrupted printing use three master tracings. This long sheet of paper may be rolled up 

and carried in the field in the form of a scroll. 

c. Intermediate control points should be added wherever possible to more precisely locate points 

along geologic discontinuities. On Figure B-2, which is a mapping sheet used at Fort Randall Dam, 

South Dakota, the horizontal distances from the center line and vertical distances from springline were 

computed and drawn on the developed plan to form a grid. When plotting a point, the mapper measures 

these two distances (horizontal distance from center line and vertical distance above or below springline) 

and plots the point at the proper tunnel stationing. To eliminate long measurements in large-diameter 

tunnels, distances were actually measured from fixed known points on the tunnel support ring beams 

(splices, bolt holes, and spreader bars). At Oahe Dam, South Dakota, horizontal and vertical distances of 

fixed features on the ring beam supports were drawn on the mapping sheets as lines so that points on 

geologic features could be plotted from the nearest ring beam reference point. On Figure B-3, which is a 

mapped portion of Oahe Dam power tunnel No. 2, a developed ring beam is shown at the top of the 

page, vertical distances from springline of identifiable fixed points on the ring beam are shown along the 

top of the mapping section, and horizontal distances from center line of these same points are shown 

along the bottom of the mapping section. The ring beam number and its tunnel station is shown along the 

right-hand edge. Excellent mapping control was thus provided on this project. In excavations not 

requiring close checks on alinement, control points may be almost nonexistent. In such cases, the mapper 

must establish his own control points. He may have to stretch a tape along the tunnel from the nearest 

spad, then mark stationing at 5- or 10-ft intervals along the walls, and use an assumed elevation at his 

reference point. Obviously, the resultant geologic log will not be as accurate, but the relative position of 

discontinuities should remain constant from tunnel wall to geologic log. 

d. The conventional method of measuring the strike, or orientation of a joint, shear, or fault, by 

magnetic needle (Brunton) compass is not reliable in most underground work because of the proximity to 

electrical circuits, reinforcing steel, or support steel. Also in some areas, the rock mass itself may be 

magnetic. To overcome this problem, an adjustable protractor can be devised. Essentially, it is an instru

ment for measuring the angle between the trend of a planar geologic defect, as measured in the horizontal 

plane, and the bearing of the tunnel center line. The protractor is fitted with a revolving pointer, which 

rotates around the center point of the protractor. The baseline of the protractor is held parallel to the 

tunnel center line, the pointer is sighted along the strike of the discontinuity, and the angle-is read on the 

protractor at the point where a line scribed on the pointer coincides with the degree lines on the 

protractor arc (Figure B-4). The strike of the geologic defect is then computed from the observed angle 

and the bearing of the tunnel. In small-diameter drifts, tunnels, adits, etc., a small, light, fixed-base 

protractor will be adequate for fairly accurate readings. In large-diameter openings, a special protractor 

may be constructed that has an adjustable baseline. The baseline of the instrument is then revolved to the 

known tunnel bearing so that direct readings of strike may be taken (Figure B-4). A circular spirit level 

bubble may be mounted on the instrument to assure that readings are in the horizontal plane. Dip 

readings are observed by using the inclinometer on a Brunton compass or pocket transit. 

B-4. Helpful Suggestions. 

a. The geologic features that have the greatest effect on the physical and engineering properties of 

the rock mass should be logged first. Geologic logging should be performed close to the heading as fresh 

rock is exposed, before the exposed walls become dust covered or smeared over, and before the geologic 

features are partially or completely covered by tunnel supports, lagging, pneumatically placed mortar,

B-3 NUREG/CR-5738
Appendix B Geologic Mapping of Tunnels and Shafts

Ring Beam Bolt Spacing

Vertical Distance From Spring Line I4 In 1 I in t1-oo

42 6 1 i g :iiN ipil 8 ; f ig iijiiiii ,t , 

"Hr" o I oc11rom 11 

l•24 6,8 ,O, [ , 12 08e64 2•2 4 68. I0,12 1 2 10e64 

'Horizontal Distlance FrornV

t-io 

"1-20 

"I- 30 

40 

"50 

60 

ro

0 

0

TUNNEL NO. 4 DIAMETER 22 Ft. STA.248 To 247

Figure B-2. Developed plan of cylindrical tunnel section, Fort Randall Dam, South Dakota

NUREG/CR-573 8

0O

B-4
Appendix B Geologic Mapping of Tunnels and Shafts 

RING BEAM DEVELOPED 

+'" + +÷ ++ T J 

I - I 

I 

VERTICAL DISTANCE FROM SPRING LINE 0 2 

A N xa.J C 

> - -- I-I I- 1,3_ 

I t / / d '-

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I II 6-

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n- , 40 . = U .. q,0 = "h -, , 

HORIZONTAL DISTANCE FROM 

VERTICAL GENTERLINE 

DOWNSTREAM POWER TUNNEL NO,

29.0 Ft. DIA. RING BEAM MONOLITH - THRU 

STRIKE STA.Z-Oý TO .a+00

Figure B-3. Developed plan of cylindrical tunnel section, Oahe Dam, South Dakota.

NUREG/CR-5738

w>

B-5
Appendix B Geologic Mapping of Tunnels and Shafts

Tunnel Wall 

Protractor has telescoping pointer 

to reach beyond corners of 

protractor frame.

ADJ USTABLE 

Set revolving base on N30 0 E 

and read N45 0 W on pointer. 

TUNNEL T.

Aline these instruments 

parallel to tunnel bearing 

(N300E in this example)

"'Read 750 

0 

FIXED BASE

Compute strike from protractor 

reading and tunnel bearing,

Figure B-4. Sketch of typical protractors used in peripheral geologic mapping.

NUREG/CR-573 8 B-6
Appendix B Geologic Mapping of Tunnels and Shafts

etc. The mapper should ensure that adequate lighting is available. Mapping should be from the back of 

the mining machine or on the drill jumbo to help the mapper reach the higher sidewalls and crown in 

large-diameter tunnels. The main geologic features, such as faults, joints, shear zones, bedding planes, 

and clay seams, should be carefully plotted first. Then as time permits, other less important features may 

be filled in between the previously plotted features on the geologic log. Additional features to be logged 

include fractures, stressed zones, fallouts, water seeps, etc. These features make up only a partial list 

because additional important geologic features will be encountered at each specific project. 

b. In large- and medium-diameter tunnels consecutive mapping sections may be printed on a long 

sheet of paper to form a scroll. This continuous length of paper can be carried on a mapping board so 

designed that only the section being mapped is exposed while the remainder of the roll is inclosed in 

boxes on each side of the mapping board. Cranks and rollers may be added to assist in moving the proper 

section onto the mapping board. The board may be faced with a piece of sheet metal to provide a smooth 

writing surface. In small or odd-shaped tunnels or drifts the mapping sheets are usually carried in 

individual, conveniently sized sections. A covered clipboard makes a good mapping board. The cover is 

to protect the mapping sheets from the ever present dust, moisture, etc., associated with underground 

excavations. 

If necessary, the mapper can extend his own control from known points, a steel tape is stretched ' 

along the tunnel and 5- or 10-ft. station intervals may be marked on the wall or supports with an aerosol 

can of spray paint. Photographs of important or unusual geologic features are a valuable addition to the 

mapping. It is also suggested that a small portable tape recorder for noting the location and attitude of 

secondary features will help the mapper, especially in adding secondary features to the mapping when 

time in the tunnels is limited. 

c. The completed geologic log of a horizontal or nearly horizontal tunnel will wrap around a mold of 

proper dimensions to form a model with the mapped features and recorded information in their proper 

position- however, the geologic log of peripheral mapping in a vertical shaft or end face will not be in its 

proper position unless the information is traced through the paper to reverse the image. The reversal of 

the image presents no particular problem because in most instances the field maps and data are 

transcribed to finished drawings in the office. Also in odd-shaped raises or in vertical shafts, it is 

difficult for the mapper to remain properly oriented unless vertical reference points around the periphery 

have been surveyed-in prior to the start of geologic mapping. 

B-5. Analysis of Data. 

a. Although peripheral geologic logging, or mapping, provides a permanent record of all geologic 

defects exposed on the walls of an underground excavation, maximum benefits cannot be gained unless 

the data are properly studied and analyzed. One study method is by cutting and trimming the drawings 

and forming them into the proper shape for three-dimensional viewing, which causes the relationship of 

discontinuities to the tunnel geometry to become much more apparent. 

b. Projection of the trace of geologic discontinuities to two-dimensional plans or profiles may be 

made, but not directly because the mapping has been done on a developed plan. One method of 

transferring data to plan is by plotting to corresponding stationing. Data may be transferred to profile, or 

cross section, by plotting the points where the discontinuities intersect measured stationing at crown, 

invert, and/or springline. Where only one point can be plotted, the trace of the discontinuity may be 

extended along a line drawn on the recorded strike or dip of a discontinuity (the use of apparent dip may

B-7 NUREG/CR-5738
Appendix B Geologic Mapping of Tunnels and Shafts 

also be necessary). Figure B-5 illustrates a method of projecting geologic data to sections drawn through 

a circular tunnel. 

c. Statistical studies may be made from the accumulated data. By counting all discontinuities per unit of length and circumference, an average piece size or block size may be determined. Plotting the 

trends ofjoints, faults, and shears on equal-area nets will help determine the major and minor joint sets 

and the preferred orientation of faults and shear zones. Another method of statistical analysis might be 

by making rosette plots of the joints and shears. 

B-6. Uses for Geologic Data. 

The value of peripheral geologic mapping has been proven many times. Below are listed some of the 

uses for this type of geological logging. 

a. Predicting geologic conditions in intermediate tunnels where driving a series of parallel tunnels. 

b. Projecting geology from the pilot drift to the full bore of a tunnel before enlarging is started. 

c. Planning tunnel support systems and selecting the best location and inclination of supplemental 

rock bolts. 

d. Maintaining a record of difficult mining areas, overbreak and fallout, and mining progress by daily notation of the heading station. This type of record is valuable in changed condition claims. 

e. Comparing cracking of concrete tunnel liners with weaknesses logged in tunnel walls. 

f. Analyzing stress conditions around tunnel openings using methods that evaluate the spacing and 

orientation of geologic discontinuities. 

g. Choosing strategic locations for various types of instrumentation to study tunnel behavior. 

h. Selecting the best locations for pore pressure-type piezometer tubes where it is desirable to 

position them to intercept particular types of discontinuities at specific elevations near previously driven 

tunnels.

NUREG/CR-573 8 B-8
Appendix B Geologic Mapping of Tunnels and Shafts

1 IGEOLOGIG LOG 

.4 SPRINGLINE 

• •.///SECTION A 

r 

Sy SECTION 

I. The strike in relation to the tunnel can be found by three different methods, 

o. Revolve springline to tunnel diameter and measure strike a'b'. 

b. Measure tangent to curve at the crown; 

c. Use measured strike. 

2. Project the intersection of the strike at the crown Is) to sections desired. 

For example, joint is at crown level at t and r respectively In sections A 13 B. 

3. Project the strike of the joint at springline level to the section desired; 

in the example, the joint Is at springllne elevation at points _n and L 

respectively In sections A and B. 

4. Line tn Is the trace of the plane oal section A, Line rl is the trace 

of the plane on section B. 

Note: Points x and y show where the joint plane intersects the tunnel 

boundary In section B. It does not Intersect the boundary in section A. 

5. Find dip (t) from distance smi. C tann-I(tunnel radi'u-- or 

ust dip m ea•ured In the field. 

Figure B-5. Method of projecting geologic data to cross sections from geologic log as developed by 

R. E. Goodman, PhD, Univ. of California.

B-9 NUREG/CR-5738
Appendix C Examples of Drilling Logs

APPENDIX C 

EXAMPLES OF DRILLING LOGS 

C-1. General. 

This appendix contains seven examples of drilling logs, five for overburden drilling and two for rock 

coring. These logs conform to the guidance presented in EM 1110-1-1806, "Presenting Subsurface 

Information in Contract Plans and Specifications." The examples are not meant to cover all possible 

subsurface conditions which may be encountered during field investigation, but are presented to give 

direction to the minimum acceptable input to completing drilling logs for the most common drilling 

activities. 

C-2. Preparation of Drilling Logs. 

Drilling logs should be made of each boring. A similar log will be prepared for each excavation 

which is constructed for the purpose of characterizing subsurface materials and geologic conditions. The 

drilling log form approved for Corps of Engineers borings and presented for example here is ENG Form 

1836 (March 1971). This form may be used as a continuation sheet or, at the option of the user, ENG 

Form 1836-A (June 1967) may be used. 

a. Scale. A scale of 1 in. = 2 ft. or larger should be used. A smaller scale may be used where, for 

example, the boring is advanced without sampling or logging, the upper portion of the log would repre

sent water, or the boring was made to identify some geologic horizon such as top of rock. Other similar 

exceptions would be allowable. 

b. Heading. All logs will have the pertinent division, installation, location, hole number, project 

identification, elevation, and page number entered on all log sheets. Items 1 through 19 on ENG Form 

1836 should be completed to the fullest extent possible as indicated in the seven examples. Boring 

numbers will be consecutive for each project. The boring numbers will be proceeded by letter symbols 

which will identify the method of drilling. These letters are as follows: 

A - Auger (Hand or Power) 

C - Core 

D - Drive 

P - Probe 

U - Undisturbed (Hydraulic or Rotary) 

Additional letters and numbers for boring identification may be used at the user's discretion. Inclusion 

of the graphic soil symbol in column c is optional. 

c. Examples. The drihing log examples of ENG FORM 1836, Figures C-I through C-7, are 

described as follows: 

Figure C-l: Overburden, disturbed, standard penetration test and auger. 

Figure C-2: Overburden, disturbed, drive. 

Figure C-3: Overburden, disturbed, auger.

C-1 NUREG/CR-5738
Appendix C Examples of Drilling Logs 

Figure C-4: Overburden, undisturbed, Denison. 

Figure C-5: Overburden, undisturbed, Shelby and auger. 

Figure C-6: Bedrock, disturbed, SPT and core. 

Figure C-7: Bedrock, core.

NUREG/CR-5738 C-2
Appendix C Examples of Drilling Logs

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Figure C-I. Overburden, disturbed, standard penetration test and auger.

C-3 NURFGICR-573 8

.1q4 /

Lerno

7. TH4ICKNESS OF OVERBIURDEN

I

.290 

/919 

Y-/75 

Af. 5 

7.0

p4 -

(MV 1-fih/6--/R y,-//o 

olraaed 96fw, w*eal'a ?r 

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C-3

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9 'TarAL CORE RECOMY FOR liORING I

L H"CQ
Appendix C Examples of Drilling Logs

1-

1836 ratmvouz eomosAvieOWSLET& 

(7PJJSwCFJ1T)

Figure C-I (concluded). Overburden, disturbed, standard penetration test and auger.

NUREG/CR-5738 C-4
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Appendix C Examples of Drilling Logs

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S. DRECTION OFU4L 140 HAEOLE -I-' - -9 

J7. THICKNESS OF OVERMURDEN It2 .'roYAL CORE RECOYERY FOR SORING 

1. TOTAL DEPTH Of MOLE Oý 0,7 0 71w;- 

II CLASIFICATOK OF MATERIALS % COft e4-f REdARR 

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Figure C-3. Overburden, disturbed, auger.

NUREG/CR-573 8C6 C-6

I t)PjLuHr, LooI .57W.0
Appendix C Examples of Drilling Logs 

V. OERBUREK TKCKHEI OF 2II. 'TOTAL OERCOER FOR81K 0 V 

5. IOEPT O RILLERl IS.T cOCK nO, RE GIT O UN ATSECT R yg 

I.~17 TOEVTIL TOPT OF' HOLE 3715./3 

OEO E OFTIKESO MAE IAS s A ¶CORE~ REOVEY OR O R EMAIC 

ELEVATIONS DEPTH LEGEND CtAtICA80 Of. -RI'ALS SAPý .~n. K 

5 ~052 

0.4- 5 ''

0,5 6 0o' 

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0.63 

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EAG FORM 1836 PrnmvIOsEairtIIsAREO ocoI-1RJETKL OLT O 

Figure C-4. Overburden, undisturbed, Denison. 

C-7 NUREG/CR-5738

z
Appendix C Examples of Drilling Logs

~L HOLE OATS 2~ /.l. - a/8 

D;ULU~//e/cQ VIINOOSET LOGe 

- e~g L. ANFACUREFe OC Ic? ,9 ,,20/K 

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PKJC OF ROLE ~ 7.HtCFOM 2836 PVRC1aJSCZRDEK -, ~ CT It TOA CORE. RA, E-VR RBRN

fr~msulci(1v 

Figure C-5. Overburden, undisturbed, Shelby and auger. 

NUREG/CR-5 738 C-8

E

/YV ---,$
Appendix C Examples of Drilling Logs

L. CILLIG AEC VZ 10 N YEC-W 

A OEH.(A .. *..* 

HOME~ ~ ~ ~~~~~~~~~T- OFDRILLyr',, 1 C ~ i LVAINC0UO 

VERISIc DEC.ef TOTALNE COOM GEK. 

* TCEI~FOVERSROEDEC 17. ELEVATION TO' OF HOLE .7 . 

OEPFN ROR ORILCO INTO 00. go.ITOTAL CORE RECOVERY FOR BORING .4 95 DEP'H CMLLEDINTOROCK0 - is. SIGif TURE OF INSPECTOR 

*TOTAL lEP"TH Or HOLv ?5.o ---

CLASIFICTIO AEIL C ORE SOý"COR AREMARKI 

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ENG FORM 1836~ PREVIOUS EDITIONS AE OB.SOLETE. PROJECTROEIo 

Figure C-6. Bedrock, disturbed, SPT and core.

C-9 NIJREG/CR-573 8
Appendix C Examples of Drilling Logs

Figure C-6 (concluded). Bedrock, disturbed, SPT and core.

NUREG/CR-573 8

I

C-1O
Appendix C Examples of Drilling Logs 

DRILLING LOG v'n0o Awrcr w.as//euE -t. PROJECT/ CaI* LIKE RO * TYPE O ITI 

L.LOCATIOK MI 14 2487P A" So. WbUACEUMF oGAIO FCI. 

I. AKE Or GRILLER A.I,. IEL E LEVTON GROUND WATER 0 . 

S. iRpIOK or HOLE 

STALE DATE4LHOLE 

LýW -C. -IT. ELEVATION TOP OF HOLE • 5 

7. THICKNESS OF OVERBURDEN C IS.'TOTAL CORE RECOVERY FOR BORING 

A. DEPTH DRILLED INKTO IROCIC I5 1. SIGMATURE OF INSPECTOR -I 

T. OTAL DEPTH or HOLE t5-5-5 5 n&A 

CLASSIFICATION OF HDA S CORE 805c RCARK 

ELEVATION DEPTH LEGEND E.cj'~IRECY.Af - I D~ t" A'S . e t nS 

4 00 

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Figure~~~I oe C-.Berc, 

C-1~ Io~ w 9.1GC-53
Appendix C Examples of Drilling Logs

Figure C-7 (continued). Bedrock, core.

NUREG/CR-5738

I

C- 12
Appendix C Examples of Drilling Logs

7o-y/drsVA6 &I,~

Figure C-7 (concluded). Bedrock, core.

C- 13 NUREG/CR-573 8
Appendix D Methods of Subsurface Exploration

APPENDIX D 

METHODS OF SUBSURFACE EXPLORATION'

'Department of the Army, 1984.

NUREG/CR-5738 D-1
APPENDIX D 

METHODS OF SUBSURFACE EXPLORATION 1

APPLICABILITY

1. Methods of Access for Sampling, Test, or Observation

00

Wash Boring 

Rotary Drilling

Percussion Drilling

Cable Drilling

Continuous Sampling or 

Displacement Boring

Pits, Trenches, Shafts, 

Tunnels 

Auger Boring 

Hollow Stem Auger 

Boring

Visual observation, photography, disturbed 

and undisturbed sampling, in situ testing 

of soil and rock. 

Recovery of remolded samples and determining 

groundwater levels, Access for undisturbed 

sampling of cohesive soils. 

Access of undisturbed or representative 

sampling through hollow stem with thin-wall 

tube sampler, core barrel, or spilt-barrel sampler. 

Cleaning out and advancing hole in soil 

between sample intervals. 

Cleaning out and advancing hole in soil 

or rock between sample intervals.

Excavation made by hand, large 

auger, or digging machinery. 

Boring advanced by hand auger 

or power auger. 

Boring advanced by means of 

Continuous-flight helix auger with 

hollow center stem. 

Boring advanced by chopping with 

light bit and by jetting with upward

deflected jet. 

Boring advanced by rotating drilling 

bit; cuttings removed by circulating 

drilling fluid. 

Boring advanced by air-operated 

Impact hammer. 

Boring advanced by repeated dropping 

of heavy bit; removal of cuttings by 

bailing. 

Boring advanced by repeated pushing of 

sampler or closed sampler is pushed to 

desired depth and sample is taken.

Depth of unprotected excavations is limited 

by groundwater or safety considerations. 

May need dewatering. 

Will not penetrated boulders or most rock. 

Should not be used with plug in coarse

grained soils. Not suitable for undisturbed 

sampling in loose sand or silt. 

Suitable for use with sampling operations in 

soil only if done with low water velocities 

and with up-ward-deflected jet. 

Drilling mud should be used in coarse

grained soils. Bottom discharge bits are not 

suitable for use with undisturbed sampling in 

soils unless combined with protruding core 

barrel, as in Denison sampler, or with 

upward-deflected jets. 

Not suitable for use in soils. 

Causes severe disturbance in soils; not 

suitable for use with undisturbed sampling 

methods. 

Effects of advance and withdrawal of 

sampler result in disturbed sections at top 

and bottom of sample. In some soils, entire 

sample may be disturbed. Best suited for use 

in cohesive soils. Continuous sampling in 

cohesionless soils may be made by 

successive reaming and cleaning of hole 

between sampling.

(Continued)

1 Department of the Army, 1984.

METHOD PROCEDURE

Detection of voids and zones of weakness 

in rock by changes in drill rate or resistance. 

Access for in situ testing or logging. 

Advancing hole in soil or rock. Access for 

sampling, in situ testing, or logging in rock. 

Penetration of hard layers, gravel, or boulders 

in auger borings. 

Recovery of representative samples of cohesive 

soils and undisturbed samples in some cohesive 

soils.

LIMITATIONS G 

0 

V 

Q

C/) 

Z 

0 

(D 

=-1 

5-I
APPENDIX D (Continued) 

METHODS OF SUBSURFACE EXPLORATION

APPLICABILITY

2. Methods of Sampling Soil and Rock

Hand-Cut Block or 

Cylindrical Sample 

Fixed-Piston Sampler 

Hydraulic Piston Sampler 

(Osterberg Sampler) 

Free-Piston Sampler 

Open Drive Sampler 

Swedish Foil Sampler 

Pitcher Sampler 

Spilt-Barrel or Split 

Spoon Sampler

Sample is cut by hand from soil exposed 

in excavation. 

Thin-walled tube is pushed into soil, 

with fixed piston in contact with top of 

sample during push. 

Thin-walled tube is pushed into soil by 

hydraulic pressure. Fixed piston in 

contact with top of sample during push. 

Thin-walled tube is pushed into soil, with. 

Piston rests on top of soil sample during 

push. 

Thin-walled, open tube is pushed into soil. 

Sample tube is pushed into soil while 

stainless steel strips unrolling from spools 

envelop sample. Piston, fixed by chain 

from surface, maintains contact with top 

of sample. 

Thin-walled tube is pushed into by spring 

above sampler while outer core bit reams 

hole. Cuttings removed by circulating 

drilling fluid. 

Spilt-barrel tube is driven into soil by blows 

of falling ram. Sampling is carried out in 

conjunction with Standard Penetration Test.

Highest quality undisturbed samples in all 

soils and in soft rock. 

Undisturbed samples in cohesive soils, silts, 

and sands above or below the water table. 

Undisturbed samples in cohesive soils, silts, and 

sands above or below the water table. 

Undisturbed samples in stiff cohesive soils. 

Representative samples in soft-to-medium 

cohesive soils and silts. 

Undisturbed samples in stiff cohesive soils. 

Representative samples in soft-to-medium 

cohesive soils and silts. 

Continuous undisturbed samples up to 66 feet 

(20 m) long in very soft to soft clays. 

Undisturbed samples in stiff, hard, brittle, 

cohesive soils and sands with cementation 

and in soft rock. Effective in sampling 

alternating hard and soft layers. Represen

tative samples in soft-to-medium cohesive 

soils and silts. Disturbed samples may be 

obtained in cohesionless materials with 

variable success. 

Representative samples in soils other than 

coarse-grained soils.

Requires accessible excavation and 

dewatering if below water table. Extreme 

care is required in sampling cohesionless 

soils. 

Some types do not have a positive means to 

prevent piston movement. 

Not possible to determine amount of sampler 

penetration during push. Does not have 

vacuum- breaker in piston. 

May not be suitable for sampling in 

cohesionless soils. Free piston provides no 

control of specific recovery ratio. 

Small diameter of tubes may not be suitable 

for sampling in cohesionless soils or for 

undisturbed sampling in uncased boreholes. 

No control of specific recovery ratio. 

Not suitable for use in soils containing 

gravel, sand layers, or shells, which may 

rupture foils and damage samples. Difficulty 

may be encountered in alternating hard and 

soft layers with squeezing of soft layers and 

reduction in thickness. Requires 

experienced operator. 

Frequently ineffective in cohesion less soils. 

Samples are disturbed and not suitable for 

tests of physical properties.

(Continued)

METHOD PROCEDURE LIMITATIONS

00

0 

0 

(D1 

0 

(5 

"-t
APPENDIX D (Continued) 

METHODS OF SUBSURFACE EXPLORATION

METHOD PROCEDURE APPLICABILITY LIMITATIONS

2. Methods of Sampling Soil and Rock (Continued) 0 

00

Gravity Corer

Auger Sampling 

Rotary Core Barrel 

Denison Sampler 

Shot Core Boring (Calyx) 

Oriented Integral Sampling 

Wash Sampling or 

Cuttings Sampling 

Submersible Vibratory 

(Vibracore) Sampler 

Underwater Piston Corer

Auger drill used to advance hole is withdrawn 

at intervals for recovery of soil samples from 

auger flights. 

Hole is advanced by core bit while core 

sample is retained within core barrel or 

within stationary inner tube. Cuttings 

removed by drilling fluid. 

Hole is advanced and reamed by core drill 

while sample is retained in nonrotating inner 

core barrel with corecatcher. Cuttings 

removed by circulating drilling fluid. 

Boring advanced by rotating single core barrel, 

which cuts by grinding with chilled steel shot 

fed with circulating wash water. Used shot 

and coarser cuttings are deposited in an 

annular cup, or calyx, above the core barrel. 

Reinforcing rod is grouted into small-diameter 

hole, then overcored to obtain an annular 

core sample. 

Cuttings are recovered from wash water or 

drilling fluid. 

Core tube is driven into soil by vibrator. 

Core tube attached to drop weight is driven 

into soil by gravity after a free fall of controlled 

Open core tube attached to drop weight is 

driven into soil by gravity after free fall.

Determine boundaries of soil layers and obtain 

samples of soil classification. 

Core samples in competent rock and hard soils with 

single-tube core barrel. Core samples in poor or 

broken rock may be obtainable with double-tube 

core barrel with bottom discharge bit. 

Undisturbed samples in stiff-to-hard cohesive soil 

soil, sand with cementation, and soft rocks. 

Disturbed sample may be obtained in cohesionless 

materials with variable success. 

Large-diameter cores and accessible boreholes in 

rock, 

Core samples in rock with preservation of joints 

and other zones of weakness. 

Samples useful in conjunction with other data for 

identification of major strata. 

Continuous representative samples in unconsolidated 

marine sediments. 

Representative samples in unconsolidated marine 

sediments. 

Representative samples at shallow depth in 

unconsolidated marine sediments.

(Continued)

Samples not suitable for physical properties or density tests. Large errors in locating 

strata boundaries may occur without close 

attention to details of procedure. In some 

soils, particle breakdown by auger or sorting 

effects may result in errors in determining 

gradation. 

Because recovery is poorest in zones of 

weakness, samples generally fail to yield 

positive information on soft seams, joints, or 

other defects in rocks. 

Not suitable for undisturbed sampling in 

loose cohesionless soils or soft cohesive 

soils. Difficulties may be experienced in 

sampling alternating hard and soft layers. 

Cannot be used in drilling at large angles to 

the vertical. Often ineffective in securing 

small-diameter cores. 

Samples are not well suited to tests of 

physical properties. 

Sample quality is not adequate for site 

investigations for nuclear facilities. 

Because of high area ratio and effects of 

vibration, samples may be disturbed. 

Samples may be seriously disturbed. 

height. Cable-supported piston remains in 

contact with soil surface during drive. 

No control of specific recovery ratio. 

Samples are disturbed.

0 

0 

V) 

CD3 

0-. 

b-t 

0'
APPENDIX D (Continued) 

METHODS OF SUBSURFACE EXPLORATION 

APPLICABILITY

3. Methods of In Situ Testing of Soil and Rock2

Standard Penetration Test 

Cone Penetrometer Test 

Field Vane Shear Test

1:A

Drive-Point Penetrometer 

Plate Bearing Test (Soil) 

Plate Bearing Test or 

Plate Jacking Test (Rock)

Split-barrel sampler is driven into soil by 

blows of free falling weight. Blow count 

for each 6 in. (15 cm) of penetration is 

recorded. 

Steel cone is pushed into soil and followed 

by subsequent advance of friction sleeve. 

Resistance is measured during both phases 

of advance. 

Four-bladed vane is pushed into undisturbed 

soil, then rotated to cause shear failure on 

cylindrical surface. Torsional resistance 

versus angular deflection is recorded. 

Expendable steel cone is driven into soil by 

blows of falling weight. Blow count versus 

penetration is recorded. 

Steel loading plate is placed on horizontal 

surface and is statically loaded, usually by 

hydraulic jack. Settlement versus time is 

recorded for each load increment. 

Bearing pad on rock surface is statically 

loaded by hydraulic jack. Deflection versus 

load is recorded.

Blow count may be used as an index of consistency or density of soil. May be used for detection of 

changes in consistency or density in clay or sands. 

May be used with empirical relationships to estimate 

relative density of clean sand. 

Detection of changes in consistency or relative 

density in clays or sands. Used to estimate static 

undrained shear strength of clay. Used with 

empirical relationships to obtain estimate of static 

compressibility of sand. 

Used to estimate in situ undrained shear strength 

and sensitivity of clays. 

Detection of gross changes in consistency or relative 

density. May be used in some coarse-grained soils. 

Estimation of strength and moduli of soil. May be 

used at ground surface, in excavations, or in 

boreholes. 

Estimation of elastic moduli of rocks masses. May 

be used at ground surface, in excavations, in 

tunnels, or in boreholes.

Extremely unreliable in silts, silty sands, or soils containing gravel. In sands below 

water table, positive head must be 

maintained in borehole. Determination of 

relative density in sands requires site

specific correlation or highly conservative use 

of published correlations. Results are 

sensitive to details of apparatus and 

procedure. 

Strength estimates require onsite verification 

by other methods of testing. 

Not suitable for use in silt, sand, or soils 

containing appreciable amounts of gravel 

or shells. May yield unconservative 

estimates of shear strength in fissured clay 

soils or where strength is strain-rate 

dependent. 

Provides no quantitative information on soil 

properties. 

Results can be extrapolated to loaded areas 

larger than bearing plate only if properties of 

soil are uniform laterally and with depth. 

Results can be extrapolated to loaded areas 

larger than bearing pad only if rock 

properties are uniform over volume of 

interest and if diameter of bearing pad is 

larger than average spacing of joints or other 

discontinuities.

(Continued)

61 

C0

METHOD PROCEDURE

LIMITATIONS

t 

t 

CD 

0 Cn 

0 

0-. 

0 

C3 

a= 

v2 

C 

S..=
APPENDIX D (Continued) 

METHODS OF SUBSURFACE EXPLORATION

PROCEDURE APPLICABILITY LIMITATIONS

3. Methods of In Situ Testing of Soil and Rock (Continued)

Pressure Meter Test 

(Dilatometer Test)

Field Pumping Test 

Borehole Field Permeability 

Test 

Direct Shear Test 

Pressure Tunnel Test 

Radial Jacking Test 

Borehole Jack Test

Z 

00

Uniform radial pressure is applied hydraulically 

over a length of borehole several times its 

diameter. Change in diameter versus pressure 

is recorded. 

Water is pumped from or into aquifer at 

constant rate through penetrating well. 

Change in piezometric level is measured 

at well and at one or more observation 

wells. Pumping pressures and flow rates 

are recorded. Packers may be used for 

pump-in pressure tests. 

Water is added to an open-ended pipe 

casing sunk to desired depth. With 

constant head tests, constant rate of 

gravity flow into hole and size of casing 

of pipe are measured. Variations include 

applied pressure tests and falling head tests. 

Block of in situ rock is isolated to permit 

shearing along a preselected surface. 

Normal and shearing loads are applied by 

jacking. Loads and displacements are 

recorded. 

Hydraulic pressure is applied to sealed-off 

length of circular tunnel, and diametral 

deformations are measured. 

Radial pressure is applied to a length of 

circular tunnel by flat jacks. Diametral 

deformations are measured. 

Load is applied to wall of borehole by two 

diametrically opposed jacks. Deformations 

and pressures are recorded.

Estimation of elastic moduli of rocks and estimation 

of shear strengths and compressibility of soils by 

empirical relationships. 

Estimation of in situ permeability of soils and rock 

mass. 

Rough approximation of in situ permeability of soils 

and rock mass. 

Measurement of shearing resistance of rock 

mass in situ. 

Determination of elastic constants of the rock 

mass in situ. 

Same as pressure tunnel test. 

Determination of elastic modulus of rock in situ. 

Capable of applying greater pressure than 

dilatometers.

(Continued)

Test results represent properties only of 

materials in near vicinity of borehole. 

Results may be misleading in testing 

materials whose properties may be 

anisotropic. 

Apparent permeability may be greatly 

influenced by local features. Effective 

permeability of rock is dependent primarily 

on frequency and distribution of joints. Test 

result in rock is representative only to extent 

that the borehole intersects a sufficient 

number of joints to be representative of the 

joint system of the rock mass. 

Pipe casing must be carefully cleaned out 

just to the bottom of the casing. Clear 

water must be used or tests may be grossly 

misleading, Measurement of local 

permeability only. 

Tests are costly. Usually variability of rock 

mass requires a sufficient number of tests to 

provide statistical control. 

Volume of rock tested is dependent on 

tunnel diameter. Cracking due to tensile 

hoop stresses may affect apparent stiffness 

of rock. 

Same as pressure tunnel test. 

Apparent stiffness may be affected by 

development of tension cracks.

METHOD

0 

0ý C,' 

-t 

(D. 

0 

trjs 

,-e 

c/1
APPENDIX D (Continued) 

METHODS OF SUBSURFACE EXPLORATION

APPLICABILITY

3. Methods of In Situ Testing of Soil and Rock (Continued)

Borehole Deformation Meter 

Inclusion Stressmeter 

Borehole Strain Gauge 

Flat Jack Test

Hydraulic Fracturing Test 

Crosshole Seismic Test 

Uphole/Downhole Seismic 

Test

C 

U) 

U) 

00

Device for measurement of diameters 

(deformation meter) is placed in borehole. 

and hole is overcored to relieve stresses on 

annular rock core containing deformation 

meter. Diameters (usually 3) are measured 

before and after overcoring. Modulus of rock 

is measured by laboratory tests on core; 

stresses are computed by elastic theory. 

Rigid stress indicating device (stressmeter) is 

placed in borehole, and hole is overcored to 

relieve stresses on annular core containing 

stressmeter. In situ stresses are computed 

by elastic theory. 

Strain gauge is cemented to bottom (end) of 

borehole, and gauge is overcored to relieve 

stresses on core-containing strain gauge. 

Stresses are computed from resulting strains 

and from modulus obtained by laboratory 

tests on core. 

Slot is drilled in rock surface producing stress 

relief in adjacent rock. Flat jack is grouted into 

slot and hydraulically pressurized. Pressure 

required to reverse deformations produced by 

stress relief is observed. 

Fluid is pumped into sealed-off portion of 

borehole with pressure increasing until 

fracture occurs. 

Seismic signal is transmitted from source in 

one borehole to receiver(s) in other borehole(s), 

and transit time is recorded. 

Seismic signal is transmitted between borehole 

and ground surface, and transit time is 

recorded.

Mp~g . 1of afi)nrur s%1,".n in snt 

Measurement of absolute stresses in situ. Does not 

require accurate knowledge of rock modulus. 

Measurement of absolute stresses in situ. Requires 

only one core drill size. 

Measurement of one component of normal stress 

in situ. Does not require knowledge of rock modulus.

Estimation of minor principal stress. 

In situ measurement of compression wave velocity 

and shear wave velocity in soils and rocks. 

In situ measurement of compression wave velocity 

and shear wave velocity in soils and rocks.

Stress field is affected by borehole. 

Analysis subiect to limitations of elastic 

theory. Two boreholes at different 

orientations are required for determination of 

complete stress field. Questionable results 

in rocks with strongly time- dependent 

properties. 

Same as above. 

Same as above. 

Stress field is affected by excavation or 

tunnel. Interpretation of test results subject 

as assumption that loading and unloading 

moduli are equal. Questionable results in 

rock with strongly time-dependent 

properties. 

Affected by anisotropy of tensile strength of 

rock. 

Requires deviation survey of boreholes to 

eliminate errors due to deviation of holes 

from vertical. Refraction of signal through 

adjacent high-velocity beds must be 

considered in interpretation. 

Apparent velocity obtained is time-average 

for all strata between source and receiver.

(Continued)

METHOD PROCEDURE LIMITATIONS

0 

0 

1-b 

-t 

cn, 

CD 

0~ 

0d 

C 

o-
APPENDIX D (Concluded) 

METHODS OF SUBSURFACE EXPLORATION

PROCEDURE APPLICABILITY LIMITATIONS

3. Methods of In Situ Testing of Soil and Rock (Continued)

Z 

LJ0 

-.0,

Electrical Resistivity Log

00

Neutron Log

Gamma-Gamma Log 

("Density Log") 

Borehole Cameras

Acoustic Velocity Log 

3-D Velocity Log

Measurement of compression wave velocity. Used 

primarily in rocks to obtain estimate of porosity. 

Measurement of compression wave and shear wave 

velocity ties in rock. Detection of void spaces, 

open fractures, and zones of weakness.

Logging tool contains transmitting transducer 

and two receiving transducers separated by 

fixed gage length. Signal is transmitted 

through rock adjacent to borehole, and transit 

time over the gage length is recorded as dif

ference in arrival times at the receivers. 

Logging tool contains transmitting transducer 

and receiving transducer separated by fixed 

gage length. Signal is transmitted through 

rock adjacent to borehole, and wave train at 

receiver is recorded. 

Apparent electrical resistivity of soil or rock in 

neighborhood of borehole is measured by 

in-hole logging tool containing one of a wide 

variety of electrode configurations. 

Neutrons are emitted into rock or soil around 

borehole by a neutron source in the logging 

tool, and a detector isolated from the source 

responds to either slow neutrons or secondary 

gamma rays. Response of detector is 

recorded. 

Gamma rays are emitted into rock around the 

borehole by a source in the logging tool, and 

a detector isolated from the source responds 

to back-scattered gamma rays. Response 

of detector is recorded. 

Film-type or television camera in a suitable 

protective container is used for observation 

of walls of borehole,

Results represent only the material 

immediately adjacent to the borehole. Can 

be obtained only in uncased, fluid-filled 

borehole. Use is limited to materials with 

P-wave velocity greater than that of 

borehole fluid. 

Results represent only the material 

immediately adjacent to the borehole. Can 

be obtained only in uncased, fluid-filled 

borehole. Correction required for variation in 

hole size. Use is limited to materials with 

P-wave velocity greater than that of borehole 

fluid. 

Can be obtained only in uncased boreholes. 

Hole must be fluid filled, or electrodes must 

be pressed against wall of hole. Apparent 

resistivity values are strongly affected by 

changes in hole diameter, strata thickness, 

resistivity contrast between adjacent strata, 

resistivity of drilling fluid, etc. 

Because of very strong borehole effects, 

results are generally not of sufficient 

accuracy for quantitative engineering uses. 

Effects of borehole size and density of 

drilling fluid must be accounted for. 

Presently not suitable for qualitative 

estimate of density in soils other than those 

of "rock-like" character. Cannot be used in 

cased boreholes. 

Results are affected by an condition that 

affects visibility.

Appropriate combinations of resistivity logs can be 

used to estimate porosity can degree of water 

saturation in rocks. In soils, may be used as 

qualitative indication of changes in void ratio or 

water content, for correlation of strata between 

boreholes, and for location of strata boundaries. 

Correlation of strata between boreholes and location 

of strata boundaries. Provides an approximation to 

water content and can be run in cased or uncased, 

fluid-filled or empty boreholes. 

Estimation of bulk density in rocks, qualitative 

indication of changes in density of soils. May 

be run in empty or fluid-filled holes. 

Detection and mapping of joints, seams, cavities, 

or other visually observable features in rock. Can 

be used in empty, uncased holes or in holes filled 

with clear water.

METHOD

0 

v) 

W 

r_ 

,-l 

(D 

0 5

0
Appendix E Spacing and Depth of Subsurface Explorations for Safety-Related Foundations 

APPENDIX E 

SPACING AND DEPTH OF SUBSURFACE EXPLORATIONS FOR SAFETY-RELATED' 

FOUNDATIONS

NUREG/CR-57-38

'Department of the Army, 1984.

E-1
APPENDIX E 

SPACING AND DEPTH OF SUBSURFACE EXPLORATIONS FOR SAFETY-RELATED' FOUNDATIONS

TYPE OF STRUCTURE 

General 

-.4 

00 

Structures including buildings, 

retaining walls, concrete dams

Earth dams, dikes, levees, 

and embankments

SPACING OF BORINGS 2 OR SOUNDINGS 

For favorable, uniform geologic conditions, where continuity of 

subsurface strata is found, the recommended spacing rs as 

indicated for the type of structure, At least one boring ,hnhjd he 

at the location of every safety-related strrruife Where vawathi 

conditions are found, spacing should be, %mn1iit, A% rVee,110d to 

obtain a clear picture of soil or rock pror-rti-;s anrl thirel vmrarr' y 

Where cavities or other discontinuities of engireerrnrg sryrtcair e 

may occur, the normal exploratory work should he supplemented by 

borings or soundings at a spacing small enough to detect such 

features. 

Principal borings: at least one boring beneath every safety

related structure. For larger, heavier structures, such as the 

containment and auxiliary buildings, at least one boring per 

10,000 ft2 (900 mi) (approximately 100-foot (300-meter) 

spacing). In addition, a number of borings along the periphery, 

at corners, and other selected locations. One boring per 100 

linear feet (30 linear meters) for essentially linear structures. 3 

Principal borings: one per 100 linear feet (30 linear meters) 

along axis of structure and at critical locations perpendicular 

to the axis to establish geological sections with groundwater 

conditions for analysis. 3

MINIMUM DEPTH OF PENETRATION 

The depth of borings should be determined on the basis of the type of 

sticsture and geologic conditions. All borings should be extended to a 

depth sufficient to define the site geology and to sample all materials that 

iay swf-ll during excavation, may consolidate subsequent to construction, 

may be instable under earthquake loading, or whose physical properties 

woiuld affect foundation behavior or stability. Where soils are very thick, 

ther raximum required depth for engineering purposes, denoted d,,,.,,. may 

ie taken as the depth at which the change in the vertical stress during or 

after construction for the combined foundation loading is less than 

10 percent of the in situ effective overburden stress. It may be necessary to 

include in the investigation program several borings to establish the soil model 

for soil-structure interaction studies. These borings may be required to 

penetrate depths greater than those depths required for general engineering 

purposes. Borings should be deep enough to define and evaluate the 

potential for deep stability problems at the site. Generally, all borings should 

extend at least 30 feet (9 meters) below the lowest part of the foundation. If 

competent rock is encountered at lesser depths than those given, borings 

should penetrate to the greatest depth where discontinuities or zones of 

weakness or alteration can affect foundations and should penetrate at least 

20 feet (6 meters) into sound rock. For weathered shale or soft rock, depths 

should be as for soils. 

At least one-fourth of the principal borings and a minimum of one boring 

per structure to penetrate into sound rock or to a depth equal to d,... 

Others to a depth below foundation elevation equal to the width of 

structure or to a depth equal to the foundation depth below the 

original ground surface, whichever is greater. 3 

Principal borings: one per 200 linear feet (60 linear meters) to d_. 

Others should penetrate all strata whose properties would affect 

the performance of the foundation. For water-impounding structures, 

to sufficient depth to define all aquifers and zones of underseepage 

that could affect the performance of structures.'

(Continued)

As determined by the final locations of safety-related structures and facilities. 

2 includes shafts or other accessible excavations that meet depth requirements. 

3 Also supplement borings or soundings that are design dependent or necessary to define anomalies, critical conditions, etc.

M C40 

CL 

tzll 

00 

(JQ 

Cd. 

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0 

(5 

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0 

CA 

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(5 

0-
APPENDIX E (Concluded) 

SPACING AND DEPTH OF SUBSURFACE EXPLORATIONS FOR SAFETY-RELATED FOUNDATIONS

SPACING OF BORINGS OR SOUNDINGS 

Principal borings: one per 200 linear feet (60 linear meters) 

along the alignment and at critical locations perpendicular to 

the alignment to establish geologic sections with groundwater 

conditions for analysis.' 

Principal borings: This may vary depending on how well site 

conditions are understood from other plant site borings. For 

variable conditions, one per 100 linear feet (30 linear meters) 

for buried pipelines; at least one boring for each footing for 

pipelines above ground.5 

Principal borings: one per 100 linear feet (30 linear meter),3 

may vary for rock tunnels, depending on rock type and 

characteristics, and planned exploratory shafts or adits. 

Principal borings: In addition to borings at the locations of 

dams or dikes, a number of borings should be used to investigate 

geologic conditions of the reservoir basin. The number and spacing 

of borings should vary with the largest concentration being near 

control structures and the coverage decreasing with distance 

upstream.

MINIMUM DEPTH OF PENETRATION 

Principal borings: one per 200 linear feet (60 linear meters) to penetrate 

into sound rock or to d,... Others to a depth below the bottom elevation 

of excavation equal to the depth of cut or to below the lowest potential 

failure zone of the slope.3 Borings should penetrate previous strata below 

which groundwater may influence stability.' 

Principal borings: For buried pipelines, one of every three to penetrate 

into sound rock or to d,,,. Others to 5 times the pipe diameters below the 

invert elevation. For pipelines above ground, depths as for foundation 

structures. " 

Principal borings: one per 200 linear feet (60 linear meters) to penetrate 

into sound rock or to d,,,. Others to 5 times the tunnel diameter below 

the invert elevation.4

'

5 

Principal borings: at least one-fourth to penetrate that portion of the 

saturation zone that may influence seepage conditions or stability. 

Others to a depth of 25 feet (7.6 meters) below reservoir bottom 

elevation.'

4 Includes temporary cuts that would affect ultimate site safety. 

5 Supplementary borings or soundings as necessary to define anomalies.

TYPE OF STRUCTURE 

Deep cuts, 4 canals

Pipelines 

Tunnels

Reservoirs, impoundments

-d 

"CD 

0

f° 

od 

-d 

o) 

0° 

o

o5 

-C

LP 

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NRC FORM 335 U.S. NUCLEAR REGULATORY COMMISSION 1. REPORT NUMBER (2-89) 

NRCM (Assigned by NRC, Add Vol., Supp., Rev., 1102, and Addendum Numbers, if any.) 3201, 3202 BIBLIOGRAPHIC DATA SHEET 

(See instructions on the reverse) 2. TITLE AND SUBI•TiILE NUE/R53 

Field Investigations for Foundations of Nuclear Power Facilities 

3. DATE REPORT PUBLISHED 

MONTH i YEAR 

ý!ovember 1999 

4. FIN OR GRANT NUMBER 

W6453 

5. AUTHOR(S) 6. TYPE OF REPORT 

N. Torres, J.P. Koester, J.L. Llopis 

7. PERIOD COVERED (Inclusive Dates) 

June 1995 - July 1999 

S. PERFORMING ORGANIZATION - NAME AND ADDRESS (If NRC, provide Division, Office or Region, U.S. Nuclear Regulatory Commission, and mailing address; if contractor, provide name and mailing address.) 

U.S. Army Corps of Engineers 

Waterways Experiment Station 

3909 Halls Ferry Road 

Vicksburg, MS 39810-6199

u. S•I"NSOU•INL UI'NLGPOR1lG A I HUN - NAME AND ADDRESS (If NRC, type 'Same as above;, if contractor, provide NRC Division, Office or Region, U.S. Nuclear Regulatory Commission, and mailing address.)

Division of Engineering Technology 

Office of Nuclear Regulatory Research 

U.S. Nuclear Regulatory Commission 

Washington, DC 20555-0001 

10. SUPPLEMENTARY NOTES 

E.G. Zurflueh, NRC Project Manager 

11. ABSTRACT (200 words or less) 

This document provides a technical basis for revision of the U.S. Nuclear Regulatory Commission Regulatory Guide 1.132, Site Investigations for Foundations of Nuclear Power Facilities, reflecting current and state-of-the-art techniques related to field site investigations. The report summarizes the processes of acquiring geological, geophysical, geotechnical, and other kinds of relevant information that may affect the construction or performance of a building or other engineered structure at selected sites. Guidance is presented for in situ studies during the various stages of site characterization. Topics range from initial information gathering, literature review, and site reconnaissance investigations, to on-site testing and the collection and 

management of samples for laboratory testing. Specific laboratory tests and techniques for the engineering analysis of soils and specific requirements for liquefaction analysis are not addressed in this document but are covered in companion technical 

basis documents.

12. KEY WORDS/DESCRIPTORS (List words or phrases that will assist researchers in ocating the report.) 13. AVAILABILITY STATEMENT 

unlimited Site investigation 14. SECURITY CLASSIFICATION Borings (rhis Page) Sampling methods unclassified 

(This Report) 

unclassified 

15. NUMBER OF PAGES 

16. PRICE 

NRC. IFORM •%•{R.q

NRC FORM 33512-89)
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NUCLEAR REGULATORY COMMISSION 

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