SOIL MECHANICS REPORTPLUM CREEK FRS NO. 10
BUDA, TEXAS

M & E Consultants
Heidenheimer, Texas-1-

Mr. Trent Street, P.E.
M & E Consultants
P.O. Box 9
Heidenheimer, TX 76533

Job 0118-002
June 22, 2018

Soil Mechanics Report
Plum Creek FRS 10
Buda, Texas

Submitted herewith are the results of the geotechnical investigation and engineering
analyses to support the proposed modifications to the existing Plum Creek Dam 10 in Buda,
Texas. Our services included a field reconnaissance and geotechnical investigation, laboratory
testing, engineering analyses, and preparation of this report.
Balcones Geotechnical, LLC (Balcones) appreciates the opportunity to provide thesegeotechnical engineering services to M & E Consultants and looks forward to our continued
association. Please do not hesitate to contact us with any questions or comments about thisreport, or if we can be of further service.
Sincerely,
BALCONES GEOTECHNICAL, LLC
TBPE Firm Registration No. F-15624

Rebecca A. Russo, P.E.
Senior Geotechnical Engineer

John A. Wooley, P.E.
Principal
Attachments
Distribution:
Addressee
File (1)

CONTENTS
PAGE
INTRODUCTION ......................................................................................................................... 1
AUTHORIZATION AND SCOPE .................................................................................................. 1
PROJECT DESCRIPTION ........................................................................................................... 2
FIELD INVESTIGATION .............................................................................................................. 2
LABORATORY INVESTIGATION ................................................................................................ 4
Consolidated Undrained Triaxial Compression ................................................................. 4
Borrow Samples ............................................................................................................... 5
Crumb Dispersion Test ..................................................................................................... 6
Soluble Sulfate Content Tests .......................................................................................... 7
Strata Descriptions ........................................................................................................... 8
SITE AND SUBSURFACE CONDITIONS .................................................................................... 9
Physiography.................................................................................................................... 9
Geology ............................................................................................................................ 9Stratigraphy and Engineering Properties ........................................................................ 10
Groundwater................................................................................................................... 11
GEOTECHNICAL EVALUATION ............................................................................................... 12
Methodology ................................................................................................................... 12
Seepage ......................................................................................................................... 12
Slope Stability................................................................................................................. 14
Settlement ...................................................................................................................... 16
GEOTECHNICAL RECOMMENDATIONS ................................................................................. 17
Upstream Slope Modifications ........................................................................................ 17
Downstream Slope Flattening and Toe Drain Installation ............................................... 17
New Principal Spillway ................................................................................................... 18
Auxiliary Spillway Modifications ...................................................................................... 21
CONSTRUCTION RECOMMENDATIONS ................................................................................ 21
Earthwork ....................................................................................................................... 21
Excavation in Borrow Areas............................................................................................ 24
Stripping and Surface Preparation .................................................................................. 25
Construction Monitoring .................................................................................................. 25
CONDITIONS ............................................................................................................................ 26-i-

LIST OF TABLES
PAGE
Table 1. Boring Summary Information ....................................................................................... 3
Table 2. CU Triaxial Test Results .............................................................................................. 5
Table 3. Borrow Boring Lab Data Summary .............................................................................. 6
Table 4. Borrow Boring Lab Data Summary .............................................................................. 7
Table 5. Soluble Sulfate Content Test Results .......................................................................... 7
Table 6. Guidelines for Stabilization of Soils Containing Sulfates .............................................. 8
Table 7. Summary of Stabilized Groundwater Measurements ..................................................11
Table 8. Hydraulic Conductivities Estimated for Seepage Model ..............................................13
Table 9. Slope Stability Design Criteria ....................................................................................15
Table 10. Summary of Estimated Material Properties...............................................................15
Table 11. Results of Slope Stability Analysis ............................................................................16

PLATES

VICINITY MAP .................................................................................................................... Plate 1
BORING LOCATION PLAN ................................................................................................ Plate 2
USGS TOPOGRAPHIC MAP .............................................................................................. Plate 3
GEOLOGIC MAP ................................................................................................................ Plate 4
SITE AND SAMPLE PHOTOGRAPHS .......................................................................... Plates 5-7
GENERALIZED SUBSURFACE PROFILE ......................................................................... Plate 8-ii-

APPENDICESAPPENDIX A – 1962 AS-BUILT DRAWINGSAPPENDIX B – FIELD PHOTOGRAPHSAPPENDIX C – BORING LOGS
Boring Logs, Keys to Terms and Symbols
APPENDIX D – LABORATORY TESTING
Grainsize Curves
Advanced Lab Testing
APPENDIX E – SLOPE STABILITY RESULTS
SLIDE Computer Output-iii-

INTRODUCTION
The project will consist of improvements to the existing Plum Creek FRS No. 10
embankment dam including wave protection on the upstream slope; flattening the downstream
slope and installation of toe drains; installation of a new principal spillway riser, horizontal
conduit pipe, and discharge basin; and modifications to the auxiliary spillway. The dam site is
located at the northeast quadrant of the intersection of FM 2001 and Satterwhite Road, as
shown on the Vicinity Map, Plate 1.
The dam is owned and operated by the Natural Resource Conservation Service (NRCS)
and Hays County. The proposed improvements are being designed by M & E Consultants(M&E). Balcones Geotechnical, LLC (Balcones) was retained by M&E to provide geotechnicalengineering services and this Soil Mechanics Report (SMR).
The following sections of this report include a discussion of authorization and scope;
project description; field and laboratory investigation procedures; site and subsurface
conditions; geotechnical evaluations and results; and recommendations for construction.
AUTHORIZATION AND SCOPE
The investigation was authorized by approval of our proposal dated January 2, 2018 andauthorized by Mr. Trent Street, P.E. of M&E. The proposal outlines the requested and agreed
upon scope of services.
The scope of the investigation included 1) drilling of 15 borings to determine subsurface
conditions within the dam footprint and borrow areas for obtaining representative samples forlaboratory testing; 2) laboratory testing to determine classification and strength properties ofembankment materials and borrow, 3) geotechnical engineering characterization and stability
analyses for proposed improvements, and 4) preparation of this report including geotechnicaldesign and construction recommendations.
A Geologic Investigation (GI) report is being submitted under separate cover, and isbeing authored by the NRCS. The Soil Mechanics Report (SMR) presented herein contains
data collected for this investigation as well as as-built information and site observations. This
SMR is intended to supplement the GI report with specific findings and recommendations basedon geotechnical analyses.

-1-Field sampling and laboratory testing were in general accordance with methods,
procedures, and practices set forth by the American Society for Testing and Materials, latest
version of Annual Book of ASTM Standards, where applicable.

PROJECT DESCRIPTION
The project will consist of modifications to an existing earthen embankment flood control
dam in Buda, Texas. According to the USACE National Inventory of Dams, the dam (TX01577)
was built in 1963, has a reported dam length of 1,788 LF and dam height of 36 feet. As-built
drawings, dated 1962, were provided to us by M&E and are included in Appendix A. The
as-built drawings report a dam height of 31 ft and a dam length of 1,654 LF.
Proposed improvements will include reconstructing the upstream slope with addition ofwave protection; flattening of the downstream slope and construction of toe drains; installationof a new principal spillway including a new inlet riser, discharge basin, and horizontal conduit
pipe; and modifications to the auxiliary spillway including a 30-ft widening and 2 ft lowering of
the control elevation. The modifications are planned to bring the dam into compliance with
TCEQ Dam Safety requirements for a high hazard dam.

FIELD INVESTIGATION
Site Reconnaissance. On January 18, 2018, Balcones personnel, Rebecca Russo,
P.E., and David Mason, P.G., visited the subject site to observe site conditions and establish
boring locations. At the site were representatives with NRCS, Hays County, and M&E. A
photographic log of the site observations during this field visit are included in Appendix B.
In general, the dam was observed to be in good condition with noted wave erosion andsmall surface sloughing along the upstream slope. A wastewater utility line was noted in the
proposed borrow area to the east of the lake impoundment, as evidenced by marked manholes.
Drilling. On January 23 through 25, eighteen (18) borings were drilled along the dam
crest, dam toe, and in proposed borrow areas. Approximate boring locations are shown on theattached Boring Location Plan, Plate 2. A summary of boring information is given in thefollowing table.

-2-

Table 1. Boring Summary Information
DrilledBoringDrill Date

GPS Coordinates

B-301

1/24/201855-97.800261457399

30.0631360773346

Dam Crest

B-601

1/23/201820-97.798736315394

30.0634351884296

Dam Toe

B-602

1/23/201820-97.799149575767

30.063302385941

Dam Toe

B-603

1/23/201830-97.799743011732

30.0630894014034

Dam Toe

B-604

1/24/201840-97.800295944141

30.0628879172365

Dam Toe

B-605

1/23/201820-97.800927111885

30.0626931575656

Dam Toe

B-606

1/24/201825-97.801507928588

30.0624922628081

Dam Toe

B-607

1/24/201820-97.802107509847

30.0623418685759

Dam Toe

B-150

1/25/201810-97.798559392376

30.0650744378205

East Borrow

B-151

1/25/201810-97.799347584174

30.0648056557227

East Borrow

B-152

1/25/201810-97.799715962831

30.0653272909095

East Borrow

B-153

1/25/201810-97.800076748797

30.0657905173372

East Borrow

B-154

1/25/201810-97.799282679301

30.0658053787738

East Borrow

B-155

1/25/201810-97.802422952588

30.0632361901515

West Borrow

B-156

1/25/201810-97.802874018834

30.064093928968

West Borrow

Depth

Location

Boring Designation Nomenclature (NRCS):
B-300 – Borings along Dam Crest
B-600 – Borings along Dam Toe
B-150 – Borrow Borings

Detailed descriptions of subsurface materials encountered at the boring locations arepresented on the Logs of Borings, included in Appendix C. Keys to Terms and Symbols usedon the logs are set forth in Appendix C, following the boring logs.
Photographs of the soil and shale samples obtained from the borings are presented on
the attached Plates 5 and 6. Photographs of bulk soil samples obtained from the borrowborings are presented on Plate 7. A Generalized Subsurface Profile through the dam centerline
along the proposed principal spillway is presented on Plate 8.
Pocket penetrometer values, in tons per square foot, and Standard Penetration Test
N-values, in blows per foot, are also shown on the logs of borings at the respective test depth.
Groundwater and/or drilling fluid observations made during drilling are presented on the boringlogs. Borings were backfilled with a mixture of bentonite and grout upon completion of drilling.

-3-

Latitude and longitude GPS coordinates obtained at boring locations using a hand-held
GPS device accurate to about 3 horizontal meters, are shown at the top of the boring logs andshould be considered approximate. Boring elevations shown on the boring logs wereinterpolated from the provided 1-ft contour plan and should be considered approximate.
The borings were drilled using a track-mounted geoprobe equipped with 1) continuous
flight augers for advancing the holes dry and recovering disturbed samples (ASTM D1452),
2) seamless push tubes for obtaining relatively undisturbed soil samples of cohesive strata(ASTM D1587), and 3) split-barrel samplers and drive weight assembly for obtaining
representative samples and measuring the penetration resistance (N values) of non-cohesive
soil strata (ASTM D1586). The dam crest boring was drilled using a truck-mounted CME drilling
rig that also included a double-tube wireline core barrel with diamond bits for obtaining 2-inch
diameter rock cores (ASTM D2113). Selected photographs of site drilling are included inAppendix B.

LABORATORY INVESTIGATION
The laboratory testing program included identification and classification testing of strata
encountered in the subsurface. Soil classification tests, including Atterberg limit determinations(ASTM D4318), and partial grain-size analyses (ASTM D422), were conducted on
representative samples of the soil strata. Unconsolidated undrained triaxial compression tests(ASTM D2850) were conducted on testable clay soil samples obtained from the borings. The
classification and compressive strength tests included natural water content determinations(ASTM D2216). The compressive strength tests also included unit dry weight determinations.
The results of the tests are tabulated on the boring logs at the sample recovery depths.
Grainsize data in graphical form and summary lab data is presented in Appendix D. Advancedlaboratory testing and borrow sample test results are presented in the following sections.
Consolidated Undrained Triaxial Compression
In addition to classification and compression testing, advanced laboratory testing
consisting of one triaxial test on a representative, testable clay sample from boring B-301 at the
18 to 19 ft depth. Advanced lab testing was conducted by TRI Environmental in Austin, Texas,
and results are included in Appendix D.

-4-

The triaxial testing consisted of consolidated-undrained (CU) triaxial compression(ASTM D4767) with pore pressure measurements. In this test, the clay sample is trimmed andloaded into a triaxial test chamber, backpressure saturated, consolidated and sheared atvarying confining pressures. From the resulting stress vs. strain and pore water pressure
measurements at three different confining pressures, the following strength parameters can be
deduced: total stress friction angle (), effective stress friction angle (’), total stress cohesionintercept (c), and effective stress cohesion intercept (c’). The results are summarized in thefollowing table.

Table 2. CU Triaxial Test Results

BoringData Reduction

Depth

MethodTotal Stress

Effective Stress

Parameters

Parameters

Cohesion,

Friction

Cohesion,

Frictionc (psf)Angle, c’ (psf)

Angle, ’B-301

Max stress ratio

363

15.9

392

22.5

18 – 19 ft

Max stress difference

881

10.8

616

17.5

As indicated in Table 2, two data reduction techniques were applied to the lab data to
determine peak strength: maximum principal stress ratio and maximum principal stressdifference. It can be seen that the data reduction technique resulted in variable strength values.
For this analysis, we used the more conservative friction angle and applied a reduction factor tothe cohesion from max stress difference method. In general, the strength envelope of clay isoftentimes curved (non-linear), lending to a lower cohesion intercept than that estimated with alinear failure envelope.

Borrow Samples
Soil pH and PI lime series tests were conducted on composite samples obtained fromthe borrow borings. The samples were combined based on the visual classification of similar
conditions. A summary of composite samples and resulting pH and PI tests for varying percent
lime is presented in the following table.

-5-Table 3. Borrow Boring Lab Data Summary
Composite Sample
Designation

CS1(Dark brown CH)

Samples Included% Lime Added(by dry weight)(Tan CH)

0

51

8.2

B-151 (0-3 ft)

4

15

12.5

B-152 (0-3.5 ft)

5

14

12.6

6

14

12.6

B-150 (7-10 ft)

0

36

8.6

B-151 (3-10 ft)

4

17

12.6

B-152 (5-10 ft)

5

17

12.7

6

17

12.7

B-155 (0-4 ft)

0

64

---

B-156 (2.5-5 ft)

0

36

---

B-153 (0-3 ft)

B-153 (5-10 ft)
B-154 (5-10 ft)

S3(Dark grayish brn CH)
S4(Tan, calcareous CH)
PI – Plasticity Index
CH – Fat Clay“---” Test not performed

pH

B-150 (0-3 ft)

B-154 (0-3 ft)

CS2

PI

Based on laboratory test results on composite borrow samples, a minimum of 4% lime isrecommended to cause the optimal pozzolanic reaction (to achieve a pH of at least 12.4), and to
sufficiently reduce the PI.
Crumb Dispersion Test
To evaluate the dispersive characteristics of proposed embankment soils, crumb
dispersion tests were performed on soil fragments from bulk samples obtained from borrowborings and combined samples.
The test is performed by immersing a small fragment (crumb) of soil, at the natural
moisture content, into about 150 ml of distilled water. After about 5 to 10 minutes, the sample isviewed and graded based on the colloidal suspension. The test results including boring
number, depth, soil description and “grade reaction” are summarized the table below. The test
results ranged from non-dispersive to slightly dispersive with one sample having a moderate
reaction.

-6-

Table 4. Borrow Boring Lab Data Summary
Boring / Sample

Grade Reaction

Depth

Sample Description

CS1

S1

Dark brown CH

1/1

CS1

S2

Dark brown CH

3/3

CS2

S1

Tan CH

2/2

CS2

S2

Tan CH

1/1

B-150

0-3 ftDark brown CH

1/1

B-151

3-10 ft

Tan and gray CH

1/1

B-153

0-3 ftDark brown CH

1/1

B-154

0-3 ftDark brown CH

1/1

Designation(after 1 hr / after 6 hrs)

B-155
6.5-10 ft
Grayish brown CH, calcareous
2/2
Grade 1: No Reaction: Crumb may slake and run out on bottom of the beaker in flat pile but nosign of cloudy water caused by colloids in suspension.
Grade 2: Slight Reaction: Bare hint of could in water at the surface of crumb. (If the cloud iseasily visible, use Group 3).
Grade 3: Moderate Reaction: Easily recognizable could of colloids in suspension. Usually
spreading out in thin streaks on bottom of beaker.
Grade 4: Strong Reaction: Colloidal cloud covers nearly who bottom of beaker, usually in a verythin skin. In extreme cases all the water in the beaker becomes cloudy.

Soluble Sulfate Content Tests
Nine soluble sulfate content tests were conducted on bulk soil samples obtained fromthe borrow borings and composite samples.
The tests were performed in accordance with TxDOT Test Methods Tex-619-J and Tex620-J to evaluate soils with regard to the phenomenon known as “sulfate induced heave.” The
results of the soluble sulfate content tests are presented in the following table.

Table 5. Soluble Sulfate Content Test Results
BoringSample Depth

Soluble Sulfate Content

CS1

S1

3,000 mg/kg

CS1

S2

3,620 mg/kg

CS2

S1

320 mg/kg

CS2

S2

140 mg/kg-7-

Table 5. Soluble Sulfate Content Test Results
BoringSample Depth

Soluble Sulfate Content

B-150

0-3 ft

100 mg/kg

B-151

3-10 ft

120 mg/kg

B-153

0-3 ft

120 mg/kg

B-154

0-3 ft

120 mg/kg

B-155

6.5-10 ft

140 mg/kg

The following table presents some general guidelines concerning the soluble sulfate
content in soils and the associated level of risk with regard to causing sulfate induced heave
when lime stabilizing subgrade soils. These general guidelines were presented in a Technical
Memorandum titled “Guidelines for Stabilization of Soils Containing Sulfates” presented at a Soil
Stabilization Seminar that was sponsored by the Lime Association of Texas.
Table 6. Guidelines for Stabilization of Soils Containing Sulfates
Soluble Sulfate Content (mg/kg or ppm)

Level of Risk*< 3,000

Low

3,000 to 5,000

Moderate

5,000 to 8,000

Moderate to High> 8,000

High to Unacceptable* Level of risk associated with routine lime stabilization procedures.

The measured sulfate contents ranged from 100 to 3,620 mg/kg but were generally lessthan 3,000 mg/kg (ppm) which is in the low level of risk category associated with lime
stabilization procedures.

Strata Descriptions
Descriptions of strata made in the field at the time the borings were drilled were modified
in accordance with results of laboratory tests and visual examination. All recovered soil
samples were classified in general accordance with ASTM D2487 and described asrecommended in ASTM D2488. Classifications of the soils and finalized descriptions of soil
strata are shown on the boring logs.

-8-

SITE AND SUBSURFACE CONDITIONS
Physiography
The project site is located in the northeast quadrant of the intersection of FM 2001 andSatterwhite Road, about 2 miles east of IH-35 in Buda, Texas. The dam site is accessed from agated entry at Satterwhite Road. A wastewater treatment plant is located adjoining the site at
the southeast corner of the dam footprint and auxiliary spillway. One wastewater utility wasobserved at the project site, east borrow area, where manholes were observed. It is understoodthat the utility mainly extends along the eastern side of the impoundment area and to the north.
The USGS Topographic Map is presented on Plate 3. The dam is situated on Brushy
Creek, within the Plum Creek Watershed district. According to the topographic map, groundsurface elevations generally range from El. 650 ft near Brushy Creek, to about El. 680 to 685 ft
at the dam abutments.
The drainage area for Dam 10 is reported as 1,210 acres, and the normal pool reservoir
is on the order of 42 acres in size, at the time of this study. An offsite pipeline (presumably gas)
extends northeast-southwest, about 600 ft south and east of the auxiliary spillway flood
elevation.
Geology
According to the Geologic Atlas of Texas, Austin Sheet1, the dam site is mapped as
being underlain by clay and shale of the Pecan Gap formation of the Taylor Group. A Geologic
Map is presented on Plate 4.
The Pecan Gap formation of the Taylor Group generally consists of highly plastic,
calcareous clay and clayshale with some limestone. The Pecan Gap was deposited in theUpper Cretaceous age as calcareous clay. With weathering, near-surface Pecan Gap becomes
fat clay with high shrink/swell potential when subjected to moisture changes.

1

Barnes, V.E. (1974), "Geologic Atlas of Texas, Austin Sheet," Second Printing 1995, Bureau of
Economic Geology, The University of Texas at Austin, map and explanatory bulletin.

-9-Stratigraphy and Engineering Properties
Subsurface conditions can best be understood by a thorough review of the Boring Logs
included in Appendix C. In general, the borings encountered embankment fill, dark brown fatclay, tan and gray fat clay, and weathered shale to the boring termination depths. A brief
description of the subsurface conditions and engineering properties for the dam crest, dam toe,and borrow borings is provided in the following sections.
Dam Crest. Boring B-301 was drilled to the 55 ft depth within the dam crest,
approximately where the new principal spillway is planned. The boring encountered 38.5 ft ofembankment fill material, further underlain by very stiff to hard tan clay and less weathered grayclayshale of the Pecan Gap formation.
The embankment fill material is described as brown, tan and gray fat clay with measured
plasticity indices of 33 and 45. Percent fines (material passing the No. 200 sieve) were 84 and86 percent. Insitu soil moisture contents ranged from 17 to 23 percent in the upper 20 ft ofembankment, and generally 25 to 35 percent in the lower depths of the embankment, above theless pervious Pecan Gap clay. Unconfined compressive strengths of testable clay samples
were 6.5 and 3.4 tsf.
Tan and gray fat clay of the Pecan Gap formation was encountered from the 38.5 to 42 ft
depth (approximate El. 646.5 to 643 ft), further underlain by less weathered gray clayshale tothe boring termination depth of 55 feet. Standard Penetration Test (SPT) blow counts weregenerally above 100 blows per foot (bpf) in the clayshale stratum.
Dam Toe. Borings B-601 through B-607 were drilled to depths of 20 to 40 feet below
existing grade. The borings encountered embankment fill material, further underlain by very stiffto hard tan clay and less weathered gray clayshale of the Pecan Gap formation.
The embankment fill material is described as brown, tan and gray fat clay with measured
plasticity indices ranging from 31 to 50 with an average of 41. Percent fines (material passing
the No. 200 sieve) ranged from 54 to 84 with an average of 76 percent. Insitu soil moisture
contents ranged from 16 to 39 with an average of 25 percent. Unconfined compressive
strengths of testable clay samples ranged from 1.2 to 3.8 with an average of 2.5 tsf.
Tan and gray fat clay of the Pecan Gap formation was encountered at depths of 9 to
11.5 feet below existing grade. The measured plasticity index in the tan and gray stratum was39, and unconfined compressive strengths were 7.3 and 3.0 tsf. Relatively less weathered grayclayshale was encountered beneath the tan and gray clay in 5 of the 7 borings. Standard-10-Penetration Test (SPT) blow counts ranged from 60 to over 100 blows per foot (bpf) in theclayshale stratum.
Borrow. Borings B-150 through B-156 were drilled to the 10 ft depth within two
proposed borrow areas. Borings B-150 through B-154 were drilled along the east impoundment
area and encountered dark brown fat clay over tan and gray fat clay to the boring termination
depths. The measured plasticity index of the upper dark brown soil material was 51 with 95
percent fines, and the measured plasticity index of the lower tan and gray fat clay was 36 with
87 percent fines.
Borings B-155 and B-156 were drilled to the 10-ft depth along the west impoundment
area and encountered dark gray fat clay, calcareous dark gray fat clay, and tan and gray fat
clay. Measured plasticity indices were 64 and 36 where the lower PI material was thecalcareous clay. Percent fines were 96 and 94. It is suspected that this area may have beenpreviously excavated.

Groundwater
Groundwater was not encountered in the borings at the time of drilling. The toe borings(B-601 through B-607) were allowed to remain open for at least 24 hours, and stabilized
groundwater was encountered in 4 of the 7 borings at depths of 0.5 to 18.5 feet below existing
grade. A summary of stabilized groundwater measurements is presented in the table below.
Table 7. Summary of Stabilized Groundwater Measurements
Estimated Boring

24-hour

24-Hour

Elev.

Groundwater Depth

Groundwater Elev.

B-601

674

10.5

663.5

B-602

668

0.5

667.5

B-603

664

21

643

B-605

658

18.5

639.5

Boring

The normal pool (riser) elevation is estimated to be El. 671 ft at the time of drilling.

-11-

GEOTECHNICAL EVALUATION
The project will include wave erosion improvements to the upstream slope, flattening of
the downstream slope, installation of a new principal spillway riser, conduit pipe, and dischargebasin, and modifications to the auxiliary spillway. For this analysis, a typical cross section atboring B-301 (approximate STA 12+00) was used for seepage and slope stability modeling.
This section roughly corresponds to the maximum dam height section, and the location of theprincipal spillway. A schematic from the model is below.
Wave Action Bermand Rock Riprap

Lime Stabilized
Layer

Embankment

Toe Drain

Foundation

Figure 1. Proposed Dam Configuration Used in Model
Methodology
The computer program SLIDE V6 by RocScience was utilized to analyze seepage andslope stability of the proposed dam configuration. For seepage analyses, the software
generates a finite element mesh for the defined geometry, material properties and boundary
conditions. The analyses can be nested to retain seepage and phreatic conditions, thenimported to evaluate slope stability.
Analyses and stability criteria for this rehabilitation project will be based on strength
definitions and minimum factors of safety as outlined in TR-60, Earth Dams and Reservoirs,
NRCS, July 2005, and engineering judgment. For items not specifically addressed in TR-60,
the geotechnical analyses will be in accordance with TCEQ, Design and Construction
Guidelines for Dams in Texas, August 2009.
Seepage
Seepage evaluations were performed using the SLIDE finite element module(RocScience). Reservoir level (left-side) boundary conditions consist of specified head equal to
the normal pool. Normal pool boundary conditions were applied to the reservoir side groundsurface and along the vertical, left side of the model. Tailwater (right-side) boundary condition-12-

consisted of specified heads equal to the ground surface along the right-side model verticaledge. Seepage face boundary conditions were applied along the downstream slope and groundsurface to the right side of the model edge, and include the proposed toe drains.
Performance Criteria. There are no specific criteria regarding seepage published in
TR-60 (NRCS, 2005) or TCEQ (2009). Seepage performance was evaluated in terms of thefollowing:•

Computed pore pressures were used for pertinent slope stability evaluations,
including long-term steady seepage and short-term undrained loading during
rapid draw down.

•

Downstream toe drains were evaluated in terms of how they would control thephreatic surface at the downstream toe of the dam, and construction
considerations.

•

Computed hydraulic gradient variations were reviewed to assess their impact on
potential erosion and piping and the need for filter control.

Material Properties. Hydraulic conductivities were estimated from laboratory test data,
published correlations, published values, and experience with similar materials. A seepage
analysis calculation packet is included in Appendix B which presents: 1) a summary ofreferenced correlations and published values, 2) presentation of laboratory test data anddetailed evaluation of materials properties for each strata, and 3) a rationale for the hydraulicconductivity parameters selected for design. Based on our evaluation presented in Appendix B,
the following hydraulic conductivity parameters were selected for use in developing the phreatic
surface.
Table 8. Hydraulic Conductivities Estimated for Seepage Model
Material

Ks (ft/min)

K2/K1

Embankment

1 x 10-7

0.25

Foundation (Natural Soil)1 x 10-7

0.25

Lime Treated Embankment

1 x 10-6

0.25

Compacted Embankment

1 x 10-7

0.25

Rock Riprap

1 x 10-3

0.25

Toe Drain

1 x 10-4

0.25

-13-

Results. The seepage analysis was performed to determine the shape of the phreatic
surface for use in the steady state and rapid draw down stability analyses presented in thefollowing section of this report. The boundary conditions included modeling of a normal poolelevation of 679.0 ft which is the proposed auxiliary spillway crest elevation, and the presence of
toe drains. Exit gradients were found to be at acceptable levels. Graphical presentation andsummary of results are presented in Appendix E.
Slope Stability
Slope stability analyses were performed to evaluate the steady-state seepage and rapiddrawdown conditions using the proposed dam configuration cross section presented previously
in Figure 1 which represents the maximum dam height.
Slope stability evaluations were performed using SLIDE V6 (RocScience) which uses
limit equilibrium procedures applied to discretized slices representing a potential slide mass toevaluate factors of safety with respect to slope stability. The Spencer method was selected forthis limit equilibrium analysis.
Performance Criteria. The slope stability analysis was considered for the steady state
seepage condition and the rapid drawdown condition. Due to minimal grading required as partof this dam rehabilitation project (i.e. no additional earth load planned), we anticipate that thedam is currently in the steady state seepage (effective stress) condition and will not achieve a
total stress condition, as modeled in the end of construction analysis. Therefore, we have notincluded a total stress, end of construction condition in this stability analysis. Additionally, theseismic condition was also neglected due to the general lack of seismic potential in central
Texas.
For conditions of steady state seepage, the phreatic surface was developed as part of
the Seepage Analysis, described previously. For this case, the NRCS requires applying uplift
forces to saturated soil zones. The uplift is modeled as a piezometric surface which begins at
the auxiliary spillway crest on the upstream side of the embankment.
As required by TR-60 the following conditions of stability were investigated in thisanalysis. The recommended minimum factors of safety (FS) are also listed for both NRCS andTECEQ 2009, which are the same.

-14-

Table 9. Slope Stability Design Criteria

Design Condition

NRCS Design Shear Strengths

Steady Seepage -Lowest shear strength from a composite

D/S slope

envelope of CD and (CU+CD)/2 envelopes

Rapid Drawdown –3-stage Analysis: Consolidated Drained (CD)U/S slope

envelope before drawdown, lowest

NRCS

TCEQ

Minimum

Minimum

FS

FS

1.5

1.5

1.2

1.2

Material Properties. Material properties for the embankment and foundation materials
are based on laboratory test results presented herein, and developing the NRCS-specified
strength envelopes for the embankment material. Shear function calculations developed for thisanalysis are included in Appendix E.
For soil materials without advanced laboratory testing, material properties were
estimated using engineering judgment and experience with similar materials. A summary of thematerial strength properties is presented in the following table.

Table 10. Summary of Estimated Material Properties

Material Layer

DrainedDrained (CU’)

Undrained (CU)

Effective Stress

Effective Stress

Total Stress(Steady State)(Rapid Drawdown)(Rapid Drawdown)c' (psf)
Embankment
Foundation Subgrade

’ (deg)

Composite shear
functionc' (psf)

’ (deg)c (psf) (deg)

200

17.5

400

10.8

200

26

200

26

---

---

150

24

50

17.5

100

10.8

150

20

100

17.5

150

10.8

Rock Riprap

0

40

0

40

---

---

Toe Drain

0

32

0

32

---

---

Topsoil

150

28

0

28

---

---

Lime Treated
Embankment
Compacted
Embankment“---” modeled as drained (CU’) strength.

-15-

Results. The SLIDE V6 computer program utilizing Spencer’s method of slices and sideforce determination employed search routines to find the theoretically critical shear surface forsteady state and rapid drawdown loading conditions. Results are presented in Appendix E andsummarized in the following table. Results indicated minimum required factors of safety satisfy
NRCS and TCEQ design criteria for slope stability.
Table 11. Results of Slope Stability Analysis
Results
Loading
Condition

SteadySeepage
Rapid
Drawdown

Shear Envelope

Minimum
FS Required

Slope

Composite:
Lowest of CD and

1.5

D/S

(CD+CU)/2
Composite:
Lowest of CD and

Boundary
Condition
Normal Pool at
679.0

Minimum
Calculated
FS
1.60

Normal Pool at
1.2

U/S

CU

679.0 to drained

1.21

lake

Settlement
The proposed modifications to the existing embankment will generally consist of removal
of up to 4 feet of existing embankment material, addition of at least 4% lime in most areas, andearthwork replacement of existing slopes and berms. A slight flattening of the downstream
slope (from 2.5H:1V to 3.0H:1V) is planned which will add perhaps 1 ft of embankment earthload on the downstream slope.
Accordingly, the resulting configuration will be sufficiently similar to the existing, and no
additional settlement is anticipated. It is noted that assessment of the current settlement
condition of the embankment is beyond the scope of this investigation; however, no appreciablesurface depressions or low areas were noted along the dam crest at the time of our site visit(see photos in Appendix B).

-16-

GEOTECHNICAL RECOMMENDATIONS
Proposed embankment dam modifications will include: improvements to upstream
slope, flattening of downstream slope and installation of toe drains, installation of a newprincipal spillway, and modifications to the auxiliary spillway. The following sections provide
geotechnical design and construction recommendations for each of the proposed
improvements.
Upstream Slope Modifications
According to the as-built drawings, the upstream slope was designed as 2.5H:1V with awave berm at the principal spillway elevation of 671.90 feet. Currently, the slope face haseroded due to wave action, with shallow surface sloughs.
Proposed modifications to the upstream slope will include regrading to a 3.0H:1V slope
configuration, construction of a new wave action berm at elevation 670.0 ft, and construction ofa rock riprap berm. The new embankment behind the riprap berm will be constructed ofcompacted earth. Above the riprap berm, the slope face will be constructed at 3H:1V with theupper 4 feet of earth being lime treated. Based on laboratory testing results presented herein, a
4% lime addition is required to sufficiently reduce the plasticity index (PI) generally below 20.
Recommendations for earthwork are provided in the Construction Recommendations section tofollow.

Downstream Slope Flattening and Toe Drain Installation
The as-built drawings included in Appendix A show the downstream slope configuration
as 2.5H:1V with a toe berm at elevation 660.0 feet. Proposed modifications will include
flattening of the downstream slope to 3H:1V, and installation of toe drains. A compacted earth
toe berm is planned along a portion of the dam at elevation 660.8 feet.
With reshaping and flattening of the downstream slope, the upper 4 feet of embankment
will be lime treated with at least 4% lime by dry weight. The purpose of the lime treatment is tolower the PI of the high PI site soils so that a 3H:1V slope configuration can be maintained longterm. Recommendations for compacted earth and lime treated embankment are provided in theConstruction Recommendations section of this report to follow.

-17-

New Principal Spillway
A new principal spillway is planned, consisting of a new riser structure, horizontal conduit
pipe, and discharge basin. The new principal spillway riser will have a crest elevation of 671.0 ft
and invert elevation of approximately 659.0 feet. Borings were not performed within the
proposed riser footprint due to the lake impoundment.
Riser Structure. According to provided preliminary 30% plans, the riser structure will besituated near dam center line STA 11+72 and will be founded approximately 5 to 8 feet below
existing grade. According to nearby boring data, subsurface conditions at the riser foundation
will likely consist of tan and gray fat clay (CH) with sand and gravel. Groundwater may bepresent.
The Geotechnical Engineer of Record should observe the foundation subgrade prior toreinforcing steel placement, to confirm a dry excavation with suitable bearing. Specifically, thefollowing is recommended regarding the riser structure foundation:
1. Within the riser structure footprint and at least 5 ft outside the footprint, remove anddispose of all vegetation and/or muck, any deleterious materials, and any additional
depth required to bear below low consistency soils.
2. Scarify the excavated subgrade at least 8 inches and recompact to at least of 95% of
the maximum dry density as determined using ASTM D698. Hold water contents
within optimum to +3 of optimum.
3. Consideration should be given to placing a seal slab on the moisture conditioned
subgrade and prior to foundation construction. The seal slab will provide a working
surface for the construction and reduce the potential for moisture change of theunderlying fat clay soils.
The geotechnical engineer should observe theoverexcavated subgrade prior to seal slab preparation to confirm suitable bearing
conditions and sufficient excavation depths.
4. If needed to bring the foundation subgrade to grade, use a soil material having a PI
less than 30, not open-graded, and containing more than 50% fines (percent passing
the No. 200 sieve).
5. Compact the structural fill to at least 95% of the maximum dry density as determinedusing ASTM D698. Hold water contents within optimum to +4 percent of optimum,and maintain compacted lift thicknesses to 6 inches or less.
6. Foundations bearing at least 12 inches below grade may be sized using an allowablebearing pressure of 1,500 psf on the compacted, approved subgrade.

-18-

7. The perimeter foundation slab should be thickened to support the riser side walls,
and bear at least 12 inches below grade for an allowable bearing pressure of 1500
psf. Higher bearing capacity is available for deeper embedment.
8. If the slab design requires a modulus of subgrade reaction, use 75 pci.
9. For concrete foundations poured in good contact with the prepared subgrade or atop
a seal slab, an allowable coefficient of friction of 0.35 may be used for sliding
resistance.
10. These recommendations do not consider scour.
Impact Basin. The proposed impact basin and concrete cradle may be designed forshallow foundation support atop a prepared subgrade. Based on preliminary plans, subgradeconditions will likely consist of tan and gray, moist high plasticity clay. Groundwater may bepresent.
The Geotechnical Engineer of Record should observe the foundation subgrade prior toreinforcing steel placement, to confirm a dry excavation with suitable bearing. Specifically, thefollowing is recommended regarding the basin structure foundation and retaining wall design:
1. Excavate to the concrete cradle and impact basin subgrade elevation, and extend
laterally as specified on the design plans.
2. The geotechnical engineer should observe the excavated subgrade to verify
potentially unsuitable soils are not present. At that time, the geotechnical engineer
will determine the presence of loose, soft or compressible material and recommend
undercut depths, if necessary.
3. If the over-excavated subgrade needs to be brought to grade, use a soil material
having a PI less than 30, not open-graded, and containing more than 50% fines(percent passing the No. 200 sieve).
4. Compact the structural fill to at least 95% of the maximum dry density as determinedusing ASTM D698. Hold water contents within optimum to +4 percent of optimum,and maintain compacted lift thicknesses to 6 inches or less.
5. Groundwater will likely be present in the basin and cradle excavation. The contractor
should be prepared to maintain a dry excavation.
6. Foundations bearing at least 12 inches below grade may be sized using an allowablebearing pressure of 1,500 psf on the compacted, approved subgrade.

-19-

7. The perimeter foundation slab should be thickened to support the riser side walls,
and bear at least 12 inches below grade for an allowable bearing pressure of 1500
psf. Higher bearing capacity is available for deeper embedment.
8. If the slab design requires a modulus of subgrade reaction, use 75 pci.
9. For concrete foundations poured in good contact with the prepared subgrade or atop
a seal slab, an allowable coefficient of friction of 0.35 may be used for sliding
resistance.
10. These recommendations do not consider scour.
11. Any loose or disturbed materials encountered at the bottom of the foundation
excavation should be removed. There should also not be any free water standing in
the excavation. The exposed subgrade should be observed by the geotechnicalengineer prior to reinforcing steel and concrete placement to confirm suitablebearing.
12. Assuming similar soils are used to backfill behind below grade walls, a dry density ofd = 110 pcf and moist unit weight of moist = 120 pcf may be used for design of below
grade structures.
13. Below grade walls may be designed in accordance with the following.
a. Walls free to rotate, with a horizontal backfill, use an “active” equivalent
fluid pressure of 95 pcf for walls that do not drain, and 60 pcf for drained
conditions.
b. For walls restrained from rotation, with a horizontal backfill, use an “atrest” equivalent fluid pressure of 105 pcf for walls that do not drain, and80 for drained condition.
c. If drainage is provided behind the walls, it should consist of a minimum of
12 inches of clean, free-draining crushed stone with a maximum particle
size between ¼ and ½ inches, and less than 5 percent fines (material
passing the No. 200 sieve). ASTM C33 Grade 67 stone is a suitablegradation. A perforated pipe should be provided in the bottom of thegravel drainage material just beyond the walls that is connected to an
outlet pipe or weep holes.
d. During construction, heavy compaction rollers should operate no closer
than 3 feet from the wall. Hand operated compaction equipment, such as
vibratory plates, should be used directly behind the wall.

-20-

Auxiliary Spillway Modifications
The preliminary design plans show the auxiliary spillway modifications to include
lowering of the spillway crest from 681.0 to 679.0, widening by 35-feet into the dam footprint,
and reconstruction of spillway berms associated with spillway widening. Borings were notdrilled along the auxiliary spillway. However, we anticipate subsurface conditions to consisthigh plasticity brown, tan and gray fat clay. Proposed construction of earthen berms should beselected and performed as recommended in the following Construction Recommendations
section of the report.

CONSTRUCTION RECOMMENDATIONS
Earthwork
Proposed earthwork should be performed in accordance with the following
recommendations.
Compacted Earth – Zone 1•

Classify as CL or CH in accordance with the Unified Soil Classification
System;•Non-dispersive; free of organic material (trees, stumps and roots), debris, orother deleterious matter.

•

Plasticity index less than 40.

•

Maximum particle size of 2 inches.

The following is recommended for Zone 1 soil placement and compaction:
1. The soil should be processed before placement so that it is reasonably uniform incomposition and moisture content. Materials should be well blended to create a
uniform material type and consistency.
2. Construct in lifts such that all lifts are bonded together and free of hydraulic defects,
specified densities are met throughout each lift, the moisture content is uniform
throughout the fill, and clods are broken down and bonded into the rest of the lift
without nesting and voids.
3. Compact to at least 95 percent of the maximum dry density as determined by thestandard Proctor compaction test (ASTM D 698). Maintain moisture contents
between optimum and 4 percent of optimum moisture content as determined by thestandard Proctor.

-21-

4. Compacted lift thicknesses should not exceed 8 inches.
5. Borrow soils more than 3 percent dry of optimum should be prewetted in the borrow
area, and should not be placed on the fill until their moisture contents haveequilibrated.
6. Compacted soils outside the range of optimum to +4 percent of optimum should be
removed and reworked off the dam.
7. Kneading-type compaction equipment, such as cleat-type rollers, should be used sothat individual lifts are integrated and that preferential planes of hydraulic conductivity
are not created in the embankment.
8. Compaction of embankment material against structures should be done with heavy
rubber tired equipment with high tire pressures wherever practical. Thoroughcompaction in these areas is critical and should be monitored carefully in the field.
Soil moisture contents for this application should be between optimum and 4 percent
above standard Proctor optimum.
9. Hand compaction equipment should be permitted only where machinery cannot be
operated. Core material compacted by hand or by small equipment should becompacted at the same moisture range and to the same density as specified in item
3 above, and in loose lifts no thicker than 4 inches. Care should be taken to prevent
displacement of structures and damage to prepared rock surfaces.

Lime Treated Earth – Zone 2•Classify as CL or CH in accordance with the Unified Soil Classification
System, before lime treatment.

•

Non-dispersive; free of organic material (trees, stumps and roots), debris, orother deleterious matter.

•

Plasticity index less than 20.

•

Maximum particle size of 2 inches.

The following is recommended for Zone 2 placement and compaction:
1. Lime Stabilize the soils in place, in horizontal lifts, in accordance with project
Construction Specifications.
2. Use hydrated lime, at a rate of 4% lime by dry weight.

-22-

3. Mix the soil-lime with a rotary mixer. During initial mixing, maintain a maximum layer
thickness of 9 inches before compaction, and achieve a maximum particle size of 3
inches. Compact or seal off the surface in order to maintain moisture during curing.
4. Cure the mixture at least 72 hours. Maintain the water content of the mixture at or
above standard optimum water content during the curing period.
5. After curing, the treated material shall be thoroughly remixed to meet the following
gradation (exclusive of non-slaking rock fragments):. Minimum passing 2-inch sieve = 100 percent
i. Minimum passing no. 4 sieve = 60 percent
6. Compact to at least 95 of the maximum dry density as determined by the standard
Proctor compaction test (ASTM D 698), at moisture contents between 0 to +4
percent of optimum.
7. Compacted lift thicknesses should not exceed 8 inches.
8. A minimum density testing frequency should include one test per lift and per 10,000
SF of fill placed.
9. In addition to field density testing, pH testing is recommended every lift and every
20,000 SF of lime stabilized earth fill to confirm sufficient lime treatment and effective
pH increase to at least 12.3. A minimum of 3 tests per lift is recommended. Areas
that do not achieve a pH of at least 12.3 should be removed from dam, reprocessed,
and replaced with lime stabilized earth that meets this requirement.
10. Borrow soils more than 3 percent dry of optimum should be prewetted in the borrow
area, and should not be placed on the fill until their moisture contents haveequilibrated to within the required moisture content range.
11. Maintain the specified moisture until the lift is covered with successive
lifts. Compacted soils outside the range of 0 to +4 percent of optimum must be
reworked and recompacted.
12. Kneading-type compaction equipment, such as sheep-foot rollers, should be used sothat individual lifts are integrated and that preferential planes of hydraulic conductivity
are not created in the embankment.
13. Compaction against structures should be done with heavy rubber tired equipmentwith high tire pressures wherever practical. Thorough compaction in these contact
areas is critical and should be monitored carefully in the field. Soil moisture contents
for this application should be between optimum and 4 percent above standard
Proctor optimum.

-23-14. Hand compaction equipment should be permitted only where machinery cannot be
operated. Material compacted by hand or by small equipment should be compacted
at the same moisture range and to the same density as specified in Item 6 above,and in loose lifts no thicker than 4 inches. Care should be taken to prevent
displacement of structures and damage to prepared surfaces.

Fine Drainfill - Zone 3. Zone 3 will consist of filter sands for the filter drain and twostage toe drains. Clean fine sand was not encountered at the site or in the proposed borrow
areas, and will likely need to be imported. A fine aggregate sand meeting the gradation as
specified in ASTM C 33 should be suitable for use.
The Zone 3 filter material should be placed in maximum 8 inch loose lifts and compactedwith a minimum of four complete overlapping passes over the entire surface with a vibratory
plate compactor until further passes will not result in greater densification and results in an
unyielding surface. Care should be taken to prevent overcompaction and breakdown of thesand particles. The proposed compaction process should be observed and approved thegeotechnical engineer or his representative.
Aggregate - Zone 4. Zone 4 will consist of bedding and rock riprap to protect the
upstream face of the embankment from erosion by wave action. Aggregate durability tests
should be provided or performed on bulk riprap samples obtained from nearby quarries
A bedding stone, such as ASTM C 33 No. 57 stone is recommended to provide
protection of the relatively fined grained upstream shell. The bedding stone should be at least 1
ft in thickness, and the riprap should be at least 3 ft in thickness. Coarse drainfill aggregate may
consist of ASTM C33 No. 89 stone.
Excavation in Borrow Areas
Excavation in proposed borrow areas consisting of dark brown fat clay, and tan and graycalcareous fat clay should proceed without difficultly. The contractor should be prepared andequipped to thoroughly mix and process hard, high plasticity clay and soft clayshale.
Depending on proposed dewatering and construction sequence, groundwater may bepresent during mass grading and processing of borrow materials for embankment construction.
It is anticipated that the contractor will have work areas to process excavated soils, andaccommodate management of soil moisture and lime application.

-24-

Stripping and Surface Preparation
The ground surface beneath areas to receive new fill should be prepared prior to thestart of embankment construction. All trees, stumps, roots, and brush should be grubbed andremoved from the embankment areas. Grasses and other vegetation should be stripped to adepth of at least 6 inches. The finished subgrade should then be proofrolled to identify any soft
areas which should be over-excavated and replaced with compacted embankment material.
After proofrolling, the subgrade should be scarified and compacted to at least 95% of the
maximum dry density determined by the standard Proctor compaction test, (ASMT D 698) andat a soil moisture within optimum to +4% of optimum.
Construction Monitoring
It is recommended that the Geotechnical Engineer of record, or a qualified
representative, be present on-site during construction to observe, monitor construction activities
and perform quality control tests. Construction monitoring performed by qualified personnel
independent of the Contractor is recommended because the performance of foundations andother structures constructed during this project will be directly related to the Contractor’s
adherence to the recommendations presented in this report and to the specifications preparedby the Designer. Additionally, unanticipated soil and/or groundwater conditions may be
encountered during construction. Qualified geotechnical personnel observing construction onsite can monitor construction activities and may aid in recognizing unanticipated subsurface
conditions and assist in reconciling these conditions with design recommendations.

-25-

CONDITIONS
Since some variation was found in subsurface conditions at boring locations, all parties
involved should take notice that even more variation may be encountered between boring
locations. Statements in the report as to subsurface variation over given areas are intended
only as estimations from the data obtained at specific boring locations.
The professional services that form the basis for this report have been performed usingthat degree of care and skill ordinarily exercised, under similar circumstances, by reputablegeotechnical engineers practicing in the same locality. No other warranty, expressed or implied,
is made as the professional advice set forth. The results contained in this report are directed at,
and intended to be utilized within, the scope of work contained in the agreement executed by
Balcones Geotechnical, LLC and client. This report is not intended to be used for any otherpurposes.

*

*

-26-

*

PLATESBG Project No. 0118-002

Site

Source: Google Earth Professional

VICINITY MAP
Plum Creek FRS No. 10
Buda, Texas
Plate 1

BG Project No. 0118-002

Source: Google Earth Professional, Imagery date 1/13/2018

BORING LOCATION PLAN
Plum Creek FRS No. 10
Buda, Texas
Plate 2

BG Project No. 0118-002

Site

Source: Google Earth Professional, Earth Point Topo Map

USGS TOPOGRAPHIC MAP
Plum Creek FRS No. 10
Buda, Texas
Plate 3

BG Project No. 0118-002

Site

LEGEND (Youngest to Oldest)
Qal – Alluvium
Qhg – High Gravel terrace deposits
Qo – Leona terrace deposits
Kknm – Upper Taylor clay
Kpg – Pecan Gap (Lower Taylor)
Ko – Ozan Formation (lower Taylor)
USGS Texas Geology Web Viewer (https://txpub.usgs.gov/dss/texasgeology/)
Kau – Austin Group limestone
Kef – Eagle Ford shale
Kbu – Buda limestone
Kdg – Del Rio shale / Georgetown limestone

GEOLOGIC MAP
Plum Creek FRS No. 10
Buda, Texas
Plate 45

BG Project No. 0118-002

2-4 ft0-2 ft4-6 ft6-8 ft8-10 ft

10-12 ft

18-19 ft

13-15 ft

19-20 ft

23-25 ft

29-30 ft

28-29 ft

33-34 ft

34-35 ft

39-40 ft

38-39 ft

43.5-45 ft

48.5-50 ft
53.5-55 ft

BORING B-301 SAMPLE PHOTOS
Plum Creek FRS No. 10
Buda, Texas
Plate 5

BG Project No. 0118-002
2-4 ft0–2 ft4-6 ft6-8 ft

B-601
10-11 ft

8-10 ft

13-14 ft

11-12 ft

14-15 ft

18-20 ft
2-4 ft0–2 ft6-7 ft
5–6 ftB-602

7-8 ft8.5-10 ft

10-11 ft

14-15 ft

13-14 ft

18-20 ft

0-2 ft2-4 ft4-6 ft0-2 ft6-8 ft8-9 ft10-11 ft

9-10 ft

11-12 ft

12-13 ft

B-603
13-14 ft
23.5-25 ft

14-15 ft

28.5-30 ft

18.5-20 ft

TOE BORING SAMPLE PHOTOS
Plum Creek FRS No. 10
Buda, Texas
Plate 6a

BG Project No. 0118-002

0-2 ft2-3 ft3-4 ft6-8 ft4-6 ft8-9 ft9-10 ft

13.5-15 ft

10-12 ft

23.5-25 ft

18.5-20 ft

28.5-30 ft

38.5-40 ft

B-604

0-2 ft2-4 ft4-6 ft6-7 ft7-8 ft8-9 ft9-10 ft

13-14 ft

14-15 ft

18.5-20 ft

B-605

TOE BORING SAMPLE PHOTOS
Plum Creek FRS No. 10
Buda, Texas

Plate 6b

BG Project No. 0118-002

0-2 ft6-8 ft4-6 ft8-10 ft

10-11 ft

13-14 ft

11-12 ft

14-15 ft

18.5-20 ft

23.5-25 ft

B-606

4-6 ft2-4 ft0-2 ft

6- ft

8-9 ft7-8 ft9-10 ft

10-11 ft

18-18.5 ft

13-15 ft

18.5-20 ft

B-607

TOE BORING SAMPLE PHOTOS
Plum Creek FRS No. 10
Buda, Texas

Plate 6c

BG Project No. 0118-002

BORROW BORING SAMPLE PHOTOS
Plum Creek FRS No. 10
Buda, Texas
Plate 7

690

690

B-301 Dam Crest
680

680

Upstream
Slope

U=6.5

Downstream
Slope
670

670

Elevation (ft)

SIMPLE FENCE - A SIZE (W/DATA) 0118-002 PLUM CREEK.GPJ FUGRO DALLAS DATA TEMPLATE.GDT 06/03/18 16:28

PI=33
P=2.75660

650

P=2.75

?
?

P=4.0

FILL
Brown, tan and gray
FAT CLAY (CH)

U=3.4

PI=45

P=2.25P=2.0

Tan and Gray CH (Pecan Gap)

N=38-50/6"

640

B-604
P=1.75P=2.25
P=3.0

660

PI=35

650

U=2.7

P=4.5
N=70

640

N=33-50/3"

Gray CLAYSHALE (Pecan Gap)
N=46-50/2"

N=40-50/1"

N=50/6"630

630

N=42-50/5"

N=39-50/5"

620

620

N=41-50/5"

Vertical Scale: As Shown
Horizontal Scale: Not to Scale

Plum Creek FRS No. 10

Distance Along Baseline (ft)

GENERALIZED SUBSURFACE PROFILE

Buda, Texas
Project No.

0118-002

Plate 8

APPENDIX A
Original Dam DrawingsAPPENDIX B
Site Photographs

PHOTO NO.
1

DESCRIPTION:

View of dam crest, facing east
1/18/2018

PHOTO NO.
2DESCRIPTION: View of downstream slope from left abutment/emergency spillway, facing east
1/18/2018

Plum CreekFRS Dam 10
BG Project 0118-002

Page 1 of 4

Wave erosion
on upstream slope

PHOTO NO.
3

DESCRIPTION: View of upstream slope, from east impoundment (borrow) area, facing south.
1/18/2018

PHOTO NO.
4DESCRIPTION: Dam crest from right abutment, facing west.
1/18/2018

Plum CreekFRS Dam 10
BG Project 0118-002

Page 2 of 4

PHOTO NO.
5DESCRIPTION: Drilling B-603, facing west.
1/23/2018

PHOTO NO.
6DESCRIPTION: Drill crew for B-301, as viewed from B-604.
1/24/2018

Plum CreekFRS Dam 10
BG Project 0118-002

Page 3 of 4

PHOTO NO.
7

DESCRIPTION: Drilling B-151, facing north
1/25/2018

PHOTO NO.
8DESCRIPTION: Drilling borrowing boring B-152, facing southeast.
1/25/2018

Plum CreekFRS Dam 10
BG Project 0118-002

Page 4 of 4

APPENDIX C
Boring Logs

LOG OF BORING NO. B-301
Plum Creek FRS No. 10
Buda, Texas
UNCONFINEDSTRENGTHTSF

PASSING NO.
200 SIEVE, %PLASTICITYINDEX (PI), %PLASTICLIMIT, %LAYER
ELEV./DEPTH

LIQUID
LIMIT, %STRATUM DESCRIPTIONUNIT DRYWEIGHT, PCF

P=4.5+PROJECT NO. 0118-002
WATER
CONTENT, %POCKET PEN, tsf
Blows/ft.
REC./RQD, %SYMBOLSAMPLESDEPTH, FT

LATTITUDE: 30.063136
LONGITUDE: -97.800261

110

6.5(U)

97

3.4(U)SURF. ELEVATION: 685±

Brown, tan and gray FAT CLAY with Sand, very stiff,
w/scattered gravel. CH (Fill)23
22

P=3.255

17
P=4.5+

17
P=4.5+

19

P=4.5+

10

17
P=4.5+

20
P=4.5+

15

23

P=4.0

BALCONES_STD 0118-002 PLUM CREEK.GPJ 0118-002 PLUM CREEK.GPJ 06/06/18 12:10

20

57

24

33

84

25
P=2.7525

29

P=2.7530

24
25

P=2.75

35

69

24

45

86

- moist from 35 to 38 ft

646.5
38.5

P=3.5

Balcones
Geotechnical
Austin, TX 78731
512.380.9969

35
19

COMPLETION DEPTH: 55.0

KEY:

DATE DRILLED: 1-24-18
WATER LEVEL / SEEPAGE:

P = Pocket Penetrometer
N = Standard Penetration Test (bpf)
U = Unconfined Compression (tsf)

UPON COMPLETION:

Plate 1a

LOG OF BORING NO. B-301
Plum Creek FRS No. 10
Buda, Texas

50

N=38-50/6"

Gray CLAYSHALE, soft, fissile, w/silt and sandpartings. (Pecan Gap)
- moist at 44 ft

UNCONFINEDSTRENGTH
TSF

UNIT DRYWEIGHT, PCF

PASSING NO.
200 SIEVE, %14

13

N=50/6"

630.0
55.0

55

BALCONES_STD 0118-002 PLUM CREEK.GPJ 0118-002 PLUM CREEK.GPJ 06/06/18 12:10

643.0
42.0

N=46-50/2"

60

PLASTICITYINDEX (PI), %SURF. ELEVATION: 685±

Tan and gray FAT CLAY, very stiff, moist,
w/calcareous nodules, sand and silt seams andpartings, scattered gravel, and ferrous staining. CH(Pecan Gap) (continued)
45

LAYER
ELEV./
DEPTH

PLASTICLIMIT, %STRATUM DESCRIPTIONLIQUID
LIMIT, %PROJECT NO. 0118-002
WATER
CONTENT, %POCKET PEN, tsf
Blows/ft.
REC./RQD, %SYMBOLSAMPLESDEPTH, FT

LATTITUDE: 30.063136
LONGITUDE: -97.800261

13

NOTES:
1. Boring was drilled dry to the 55 ft depth, andgroundwater was not encountered. Moist soil
conditions are noted at the 35 ft depth.
2. The boring was advanced using a truck mounted
CME 75.
3. The boring was backfilled with a mixture of soil
cuttings and bentonite.

65

70

75

Balcones
Geotechnical
Austin, TX 78731
512.380.9969

COMPLETION DEPTH: 55.0

KEY:

DATE DRILLED: 1-24-18
WATER LEVEL / SEEPAGE:

P = Pocket Penetrometer
N = Standard Penetration Test (bpf)
U = Unconfined Compression (tsf)

UPON COMPLETION:

Plate 1b

LOG OF BORING NO. B-601
Plum Creek FRS No. 10
Buda, Texas

61

20

41

54

UNCONFINEDSTRENGTHTSF

PASSING NO.
200 SIEVE, %26

UNIT DRYWEIGHT, PCF

PLASTICITYINDEX (PI), %LAYER
ELEV./
DEPTH

PLASTICLIMIT, %STRATUM DESCRIPTIONLIQUID
LIMIT, %P=1.5

PROJECT NO. 0118-002
WATER
CONTENT, %POCKET PEN, tsf
Blows/ft.
REC./RQD, %SYMBOLSAMPLESDEPTH, FT

LATTITUDE: 30.063435
LONGITUDE: -97.798736

105

3.8(U)SURF. ELEVATION: 674±

Brown, tan and gray FAT CLAY with Sand, firm tovery stiff, w/calcarous particles and scattered gravel.
CH (Fill)

P=0.755

P=0.75P=3.2522

P=3.2510
P=0.75P=4.5+

Tan and gray FAT CLAY, firm to hard, slightly blocky,
calcareous, w/calcareous nodules, sand and silt
seams and partings, scattered gravel, and ferrous
staining. CH (Pecan Gap)

663.0
11.0

15

P=4.5+

654.0
20.0

BALCONES_STD 0118-002 PLUM CREEK.GPJ 0118-002 PLUM CREEK.GPJ 06/06/18 17:51

20

25

NOTES:
1. Boring was advanced dry to the 20-ft depth, andthe borehole was dry upon completion.
2. After 24 hrs, groundwater was measured at the10.5 ft depth, and the borehole caved at the 13.5 ft
depth.
3. Soil samples were obtained using direct-pushgeoprobe and auger cuttings.

30

35

Balcones
Geotechnical
Austin, TX 78731
512.380.9969

COMPLETION DEPTH: 20.0

KEY:

DATE DRILLED: 1-23-18
WATER LEVEL / SEEPAGE:

P = Pocket Penetrometer
N = Standard Penetration Test (bpf)
U = Unconfined Compression (tsf)

UPON COMPLETION:

Plate 2

LOG OF BORING NO. B-602
Plum Creek FRS No. 10
Buda, Texas

77

27

50

79

UNCONFINEDSTRENGTHTSF

PASSING NO.
200 SIEVE, %39

UNIT DRYWEIGHT, PCF

PLASTICITYINDEX (PI), %LAYER
ELEV./
DEPTH

PLASTICLIMIT, %STRATUM DESCRIPTIONLIQUID
LIMIT, %P=0.75PROJECT NO. 0118-002
WATER
CONTENT, %POCKET PEN, tsf
Blows/ft.
REC./RQD, %SYMBOLSAMPLESDEPTH, FT

LATTITUDE: 30.063302
LONGITUDE: -97.799150

29

98

1.2(U)

22

106

3(U)

SURF. ELEVATION: 668±

Brown, tan and gray FAT CLAY with Sand, firm tovery stiff, w/calcarous particles and scattered gravel.
CH (Fill)

P=0.5

5

P=1.0

P=2.5

- calcareous, w/gravel from 8 to 9 ft
10

N=12

Tan and gray FAT CLAY, very stiff to hard, slightly
blocky, calcareous, w/calcareous nodules, sand andsilt seams and partings, scattered gravel, and ferrous
staining. CH (Pecan Gap)

659.0
9.0

P=4.5+

15

P=4.5+

648.0
20.0

BALCONES_STD 0118-002 PLUM CREEK.GPJ 0118-002 PLUM CREEK.GPJ 06/06/18 17:51

20

25

NOTES:
1. Boring was advanced dry to the 20-ft depth, andthe borehole was dry upon completion.
2. After 24 hrs, groundwater was measured at the 0.5
ft depth, and the borehole caved at the 10-ft depth.
3. Soil samples were obtained using direct-pushgeoprobe and auger cuttings.

30

35

Balcones
Geotechnical
Austin, TX 78731
512.380.9969

COMPLETION DEPTH: 20.0

KEY:

DATE DRILLED: 1-23-18
WATER LEVEL / SEEPAGE:

P = Pocket Penetrometer
N = Standard Penetration Test (bpf)
U = Unconfined Compression (tsf)

UPON COMPLETION:

Plate 3

LOG OF BORING NO. B-603
Plum Creek FRS No. 10
Buda, Texas

10
P=4.5+PASSING NO.
200 SIEVE, %1.3(U)

114

7.3(U)- calcareous, w/gravel from 7 to 8.5 ft
Tan and gray FAT CLAY, very stiff to hard, slightly
blocky, calcareous, w/calcareous nodules, sand andsilt seams and partings, scattered gravel, and ferrous
staining. CH (Pecan Gap)

655.0
9.0

16

50

15

35

73

22

60

21

39

85

18

P=4.5+

15

BALCONES_STD 0118-002 PLUM CREEK.GPJ 0118-002 PLUM CREEK.GPJ 06/06/18 17:52

UNCONFINEDSTRENGTH
TSF

P=3.2525

PLASTICITYINDEX (PI), %

30

P=2.0

P=3.752091

SURF. ELEVATION: 664±

Brown, tan and gray FAT CLAY with Sand, stiff to very
stiff, w/calcarous particles and scattered gravel. CH(Fill)

P=1.25

5PLASTICLIMIT, %LAYER
ELEV./DEPTH

LIQUID
LIMIT, %STRATUM DESCRIPTIONUNIT DRYWEIGHT, PCF

P=1.0

PROJECT NO. 0118-002
WATER
CONTENT, %POCKET PEN, tsf
Blows/ft.
REC./RQD, %SYMBOLSAMPLESDEPTH, FT

LATTITUDE: 30.063089
LONGITUDE: -97.799743

N=43

Gray CLAYSHALE, soft, fissile, calcareous, w/silt andsand partings. (Pecan Gap)

644.0
20.0

N=35-50/5"

N=35-50/5"

634.0
30.0

30

35

Balcones
Geotechnical
Austin, TX 78731
512.380.9969

NOTES:
1. Boring was advanced dry to the 30-ft depth, andthe borehole was dry upon completion.
2. After 24 hrs, groundwater was measured at the21-ft depth, and the borehole caved at 25 ft
3. Soil samples were obtained using direct-pushgeoprobe and auger cuttings.

COMPLETION DEPTH: 30.0

KEY:

DATE DRILLED: 1-23-18
WATER LEVEL / SEEPAGE:

P = Pocket Penetrometer
N = Standard Penetration Test (bpf)
U = Unconfined Compression (tsf)

UPON COMPLETION:

Plate 4

LOG OF BORING NO. B-604
Plum Creek FRS No. 10
Buda, Texas

53

18

35

73

UNCONFINEDSTRENGTHTSF

PASSING NO.
200 SIEVE, %20

UNIT DRYWEIGHT, PCF

PLASTICITYINDEX (PI), %LAYER
ELEV./
DEPTH

PLASTICLIMIT, %P=2.25STRATUM DESCRIPTIONLIQUID
LIMIT, %P=1.75PROJECT NO. 0118-002
WATER
CONTENT, %POCKET PEN, tsf
Blows/ft.
REC./RQD, %SYMBOLSAMPLESDEPTH, FT

LATTITUDE: 30.062888
LONGITUDE: -97.800296

106

2.7(U)SURF. ELEVATION: 659±

Brown, tan and gray FAT CLAY with Sand, stiff to very
stiff, w/calcarous particles and scattered gravel. CH(Fill)

P=3.0
P=3.0

5

P=4.0
P=3.0
P=2.25P=2.0- calcareous, w/gravel from 8.5 to 10 ft

10
P=4.5

15

BALCONES_STD 0118-002 PLUM CREEK.GPJ 0118-002 PLUM CREEK.GPJ 06/06/18 17:52

20

N=70

Tan and gray FAT CLAY, hard, slightly blocky,
calcareous, w/calcareous nodules, sand and silt
seams and partings, scattered gravel, and ferrous
staining. CH (Pecan Gap)
Gray CLAYSHALE, soft, fissile, calcareous, w/silt andsand partings. (Pecan Gap)

648.0
11.0

21

645.0
14.0

N=33-50/3"

N=40-50/1"

25

30

35

N=42-50/5"

NOTES:
1. Boring was advanced dry to the 40-ft depth, andthe borehole was dry upon completion.
N=39-50/5" 2. After 24 hrs, the borehole was dry, and caved atthe 31 ft depth.
3. Soil samples were obtained using direct-pushgeoprobe and auger cuttings.

N=41-50/5"

Balcones
Geotechnical
Austin, TX 78731
512.380.9969

619.0

COMPLETION DEPTH: 40.0

KEY:

DATE DRILLED: 1-24-18
WATER LEVEL / SEEPAGE:

P = Pocket Penetrometer
N = Standard Penetration Test (bpf)
U = Unconfined Compression (tsf)

UPON COMPLETION:

Plate 5a

LOG OF BORING NO. B-605
Plum Creek FRS No. 10
Buda, Texas

66

25

41

80

29

74

25

49

78

UNCONFINEDSTRENGTHTSF

PASSING NO.
200 SIEVE, %24

UNIT DRYWEIGHT, PCF

PLASTICITYINDEX (PI), %LAYER
ELEV./
DEPTH

PLASTICLIMIT, %STRATUM DESCRIPTIONLIQUID
LIMIT, %P=1.5

PROJECT NO. 0118-002
WATER
CONTENT, %POCKET PEN, tsf
Blows/ft.
REC./RQD, %SYMBOLSAMPLESDEPTH, FT

LATTITUDE: 30.062693
LONGITUDE: -97.800927

105

3.1(U)SURF. ELEVATION: 658±

Brown, tan and gray FAT CLAY with Sand, stiff to very
stiff, w/calcarous particles and scattered gravel. CH(Fill)

P=2.0

5

P=3.5

P=2.75P=2.75- calcareous, w/gravel from 8.5 to 10 ft

10P=3.25P=4.5+

Tan and gray FAT CLAY, hard, slightly blocky,
calcareous, w/calcareous nodules, sand and silt
seams and partings, scattered gravel, and ferrous
staining. CH (Pecan Gap)

15

Gray CLAYSHALE, soft, fissile, calcareous, w/silt andsand partings. (Pecan Gap)

BALCONES_STD 0118-002 PLUM CREEK.GPJ 0118-002 PLUM CREEK.GPJ 06/06/18 17:52

20

N=35-50/6"

25

647.0
11.0

21

642.0
16.0

638.0
20.0

NOTES:
1. Boring was advanced dry to the 20-ft depth, andthe borehole was dry upon completion.
2. After 24 hrs, groundwater was measured at the18.5 ft depth, and the borehole cased at the 19-ft
depth.
3. Soil samples were obtained using direct-pushgeoprobe and auger cuttings.

30

35

Balcones
Geotechnical
Austin, TX 78731
512.380.9969

COMPLETION DEPTH: 20.0

KEY:

DATE DRILLED: 1-23-18
WATER LEVEL / SEEPAGE:

P = Pocket Penetrometer
N = Standard Penetration Test (bpf)
U = Unconfined Compression (tsf)

UPON COMPLETION:

Plate 6

LOG OF BORING NO. B-606
Plum Creek FRS No. 10
Buda, Texas

72

24

48

84

UNCONFINEDSTRENGTHTSF

PASSING NO.
200 SIEVE, %28

UNIT DRYWEIGHT, PCF

PLASTICITYINDEX (PI), %LAYER
ELEV./
DEPTH

PLASTICLIMIT, %STRATUM DESCRIPTIONLIQUID
LIMIT, %P=2.25PROJECT NO. 0118-002
WATER
CONTENT, %POCKET PEN, tsf
Blows/ft.
REC./RQD, %SYMBOLSAMPLESDEPTH, FT

LATTITUDE: 30.062492
LONGITUDE: -97.801508

98

2(U)

SURF. ELEVATION: 658±

Brown, tan and gray FAT CLAY with Sand, very stiff,
w/calcarous particles and scattered gravel. CH (Fill)

P=3.0

5

P=4.5

P=2.5

- w/gravel and organics from 8 to 9 ft

25

P=2.5

10

24
P=1.25P=4.5+

15

Tan and gray FAT CLAY, hard, slightly blocky,
calcareous, w/calcareous nodules, sand and silt
seams and partings, scattered gravel, and ferrous
staining. CH (Pecan Gap)

Gray CLAYSHALE, soft, fissile, calcareous, w/silt andsand partings. (Pecan Gap)

BALCONES_STD 0118-002 PLUM CREEK.GPJ 0118-002 PLUM CREEK.GPJ 06/06/18 17:52

20

25

50

19

31

79

646.5
11.5

641.5
16.5

N=33-50/6"

N=36-50/4"

30

633.0
25.0

NOTES:
1. Boring was advanced dry to the 25-ft depth, andthe borehole was dry upon completion.
2. After 24 hrs, the borehole was dry, and caved at 23
feet.
3. Soil samples were obtained using direct-pushgeoprobe and auger cuttings.

35

Balcones
Geotechnical
Austin, TX 78731
512.380.9969

COMPLETION DEPTH: 25.0

KEY:

DATE DRILLED: 1-24-18
WATER LEVEL / SEEPAGE:

P = Pocket Penetrometer
N = Standard Penetration Test (bpf)
U = Unconfined Compression (tsf)

UPON COMPLETION:

Plate 7

LOG OF BORING NO. B-607
Plum Creek FRS No. 10
Buda, Texas

66

24

42

82

UNCONFINEDSTRENGTHTSF

PASSING NO.
200 SIEVE, %29

UNIT DRYWEIGHT, PCF

PLASTICITYINDEX (PI), %LAYER
ELEV./
DEPTH

PLASTICLIMIT, %STRATUM DESCRIPTIONLIQUID
LIMIT, %P=1.25PROJECT NO. 0118-002
WATER
CONTENT, %POCKET PEN, tsf
Blows/ft.
REC./RQD, %SYMBOLSAMPLESDEPTH, FT

LATTITUDE: 30.062342
LONGITUDE: -97.802108

106

3.5(U)SURF. ELEVATION: 658±

Brown, tan and gray FAT CLAY with Sand, stiff to very
stiff, w/calcarous particles and scattered gravel. CH(Fill)

P=1.5

5

P=2.25

P=2.5

P=1.7510

P=4.5+

Tan and gray FAT CLAY, hard, slightly blocky,
calcareous, w/calcareous nodules, sand and silt
seams and partings, scattered gravel, and ferrous
staining. CH (Pecan Gap)

N=60

Gray CLAYSHALE, soft, fissile, w/silt and sandpartings. (Pecan Gap)

P=2.5

647.0
11.0

21

15

BALCONES_STD 0118-002 PLUM CREEK.GPJ 0118-002 PLUM CREEK.GPJ 06/06/18 17:52

20

25

640.0
18.0
638.0
20.0

NOTES:
1. Boring was advanced dry to the 20-ft depth, andthe borehole was dry upon completion.
2. After 24 hrs, the borehole was dry, and caved at
18.5 feet.
3. Soil samples were obtained using direct-pushgeoprobe and auger cuttings.

30

35

Balcones
Geotechnical
Austin, TX 78731
512.380.9969

COMPLETION DEPTH: 20.0

KEY:

DATE DRILLED: 1-24-18
WATER LEVEL / SEEPAGE:

P = Pocket Penetrometer
N = Standard Penetration Test (bpf)
U = Unconfined Compression (tsf)

UPON COMPLETION:

Plate 8

LOG OF BORING NO. B-150
Plum Creek FRS No. 10
Buda, Texas

P=1.75P=2.755

P=3.0

UNCONFINEDSTRENGTH
TSF

UNIT DRYWEIGHT, PCF

PASSING NO.
200 SIEVE, %PASSING NO.4
SIEVE, %SURF. ELEVATION: 678±

Dark grayish brown FAT CLAY, stiff to very stiff,
w/calcareous nodules, sand, scattered organics, andtrace gravel. CH

P=3.0
P=3.5

LAYER
ELEV./
DEPTH

PLASTICITYINDEX (PI), %STRATUM DESCRIPTIONLIQUID
LIMIT, %PROJECT NO. 0118-002
WATER
CONTENT, %POCKET PEN, tsf
Blows/ft.
REC./RQD, %SYMBOLSAMPLESDEPTH, FT

LATTITUDE: 30.065074
LONGITUDE: -97.798559

Tan and gray FAT CLAY, very stiff to hard, slightly
blocky, calcareous, w/calcareous nodules, sand andsilt seams and partings, scattered gravel, and ferrous
staining. CH (Pecan Gap)

675.0
3.0

P=2.5
P=2.5
P=3.25P=4.25BALCONES_STD_25FT 0118-002 PLUM CREEK.GPJ 0118-002 PLUM CREEK.GPJ 06/05/18 11:45

10

668.0
10.0

P=4.5+

15

NOTES:
1. Boring was advanced dry to the 10-ft depth, and no
groundwater was encountered.
2. Soil samples were obtained using direct-pushgeoprobe and auger cuttings.
3. Bulk samples from auger cuttings were obtained
from 0-3 ft, 3-7.5 ft, and 7.5-10 ft.

20

Balcones
Geotechnical
Austin, TX 78731
512.380.9969

COMPLETION DEPTH: 10.0

KEY:

DATE DRILLED: 1-25-18
WATER LEVEL / SEEPAGE: Not Observed

P = Pocket Penetrometer
N = Standard Penetration Test (bpf)
U = Unconfined Compression (tsf)

UPON COMPLETION: Not Observed
0

Plate 9

LOG OF BORING NO. B-151
Plum Creek FRS No. 10
Buda, Texas

P=0.25P=0.25P=1.25
P=2.5

5

P=3.5

UNIT DRYWEIGHT, PCF

PASSING NO.
200 SIEVE, %UNCONFINEDSTRENGTH
TSF

SURF. ELEVATION: 672±

PASSING NO.4
SIEVE, %LAYER
ELEV./
DEPTH

PLASTICITYINDEX (PI), %STRATUM DESCRIPTIONLIQUID
LIMIT, %PROJECT NO. 0118-002
WATER
CONTENT, %POCKET PEN, tsf
Blows/ft.
REC./RQD, %SYMBOLSAMPLESDEPTH, FT

LATTITUDE: 30.064806
LONGITUDE: -97.799348

Dark grayish brown FAT CLAY, soft, w/calcareous
nodules, sand, scattered organics, and trace gravel.
CH
Tan and gray FAT CLAY, stiff to very stiff, slightly
blocky, calcareous, w/calcareous nodules, sand andsilt seams and partings, scattered gravel, and ferrous
staining. CH (Pecan Gap)

669.5
2.5

P=1.25P=2.25P=2.75P=4.0- hard below 9 ft

BALCONES_STD_25FT 0118-002 PLUM CREEK.GPJ 0118-002 PLUM CREEK.GPJ 06/05/18 11:45

10

662.0
10.0

P=4.5+

15

NOTES:
1. Boring was advanced dry to the 10-ft depth, and no
groundwater was encountered.
2. Soil samples were obtained using direct-pushgeoprobe and auger cuttings.
3. Bulk samples from auger cuttings were obtained
from 0-3 ft and 3-10 ft.

20

Balcones
Geotechnical
Austin, TX 78731
512.380.9969

COMPLETION DEPTH: 10.0

KEY:

DATE DRILLED: 1-25-18
WATER LEVEL / SEEPAGE: Not Observed

P = Pocket Penetrometer
N = Standard Penetration Test (bpf)
U = Unconfined Compression (tsf)

UPON COMPLETION: Not Observed
0

Plate 10

LOG OF BORING NO. B-152
Plum Creek FRS No. 10
Buda, Texas

P=0.75
P=1.5

UNIT DRYWEIGHT, PCF

PASSING NO.
200 SIEVE, %UNCONFINEDSTRENGTH
TSF

SURF. ELEVATION: 671±

PASSING NO.4
SIEVE, %LAYER
ELEV./
DEPTH

PLASTICITYINDEX (PI), %STRATUM DESCRIPTIONLIQUID
LIMIT, %PROJECT NO. 0118-002
WATER
CONTENT, %POCKET PEN, tsf
Blows/ft.
REC./RQD, %SYMBOLSAMPLESDEPTH, FT

LATTITUDE: 30.065327
LONGITUDE: -97.799716

Dark grayish brown FAT CLAY, firm to stiff,
w/calcareous nodules, sand, scattered organics, andtrace gravel. CH

P=1.25P=1.0

5P=1.25P=2.75

Tan and gray FAT CLAY, stiff to hard, slightly blocky,
calcareous, w/calcareous nodules, sand and silt
seams and partings, scattered gravel, and ferrous
staining. CH (Pecan Gap)

667.5
3.5

P=4.0

- gravel layer at 7 ft
P=4.5
P=3.25BALCONES_STD_25FT 0118-002 PLUM CREEK.GPJ 0118-002 PLUM CREEK.GPJ 06/05/18 11:46

10

661.0
10.0

P=3.25

15

NOTES:
1. Boring was advanced dry to the 10-ft depth, and no
groundwater was encountered.
2. Soil samples were obtained using direct-pushgeoprobe and auger cuttings.
3. Bulk samples from auger cuttings were obtained
from 0-3.5 ft and 3.5-10 ft.

20

Balcones
Geotechnical
Austin, TX 78731
512.380.9969

COMPLETION DEPTH: 10.0

KEY:

DATE DRILLED: 1-25-18
WATER LEVEL / SEEPAGE: Not Observed

P = Pocket Penetrometer
N = Standard Penetration Test (bpf)
U = Unconfined Compression (tsf)

UPON COMPLETION: Not Observed
0

Plate 11

LOG OF BORING NO. B-153
Plum Creek FRS No. 10
Buda, Texas

P=1.25P=1.255P=1.25

UNCONFINEDSTRENGTH
TSF

UNIT DRYWEIGHT, PCF

PASSING NO.
200 SIEVE, %PASSING NO.4
SIEVE, %SURF. ELEVATION: 672±

Dark grayish brown FAT CLAY, stiff, w/calcareous
nodules, sand, scattered organics, and trace gravel.
CH

P=1.0
P=1.25LAYER
ELEV./
DEPTH

PLASTICITYINDEX (PI), %STRATUM DESCRIPTIONLIQUID
LIMIT, %PROJECT NO. 0118-002
WATER
CONTENT, %POCKET PEN, tsf
Blows/ft.
REC./RQD, %SYMBOLSAMPLESDEPTH, FT

LATTITUDE: 30.065791
LONGITUDE: -97.800077

Tan and gray FAT CLAY, stiff to hard, slightly blocky,
calcareous, w/calcareous nodules, sand and silt
seams and partings, scattered gravel, and ferrous
staining. CH (Pecan Gap)

669.0
3.0

P=3.0

- gravel from 6 to 7 ft
P=4.5
P=4.5+
P=4.0

BALCONES_STD_25FT 0118-002 PLUM CREEK.GPJ 0118-002 PLUM CREEK.GPJ 06/05/18 11:46

10

662.0
10.0

P=4.0

15

NOTES:
1. Boring was advanced dry to the 10-ft depth, and no
groundwater was encountered.
2. Soil samples were obtained using direct-pushgeoprobe and auger cuttings.
3. Bulk samples from auger cuttings were obtained
from 0-3 ft, 3-5 ft, and 5-10 ft.

20

Balcones
Geotechnical
Austin, TX 78731
512.380.9969

COMPLETION DEPTH: 10.0

KEY:

DATE DRILLED: 1-25-18
WATER LEVEL / SEEPAGE: Not Observed

P = Pocket Penetrometer
N = Standard Penetration Test (bpf)
U = Unconfined Compression (tsf)

UPON COMPLETION: Not Observed
0

Plate 12

LOG OF BORING NO. B-154
Plum Creek FRS No. 10
Buda, Texas

P=0.75P=2.75

UNIT DRYWEIGHT, PCF

PASSING NO.
200 SIEVE, %UNCONFINEDSTRENGTH
TSF

SURF. ELEVATION: 677±

PASSING NO.4
SIEVE, %LAYER
ELEV./
DEPTH

PLASTICITYINDEX (PI), %STRATUM DESCRIPTIONLIQUID
LIMIT, %PROJECT NO. 0118-002
WATER
CONTENT, %POCKET PEN, tsf
Blows/ft.
REC./RQD, %SYMBOLSAMPLESDEPTH, FT

LATTITUDE: 30.065805
LONGITUDE: -97.799283

Dark grayish brown FAT CLAY, firm to very stiff,
w/calcareous nodules, sand, scattered organics, andtrace gravel. CH

P=3.0
P=3.5

5

P=3.0
P=4.5+

Tan and gray FAT CLAY, very stiff to hard, slightly
blocky, calcareous, w/calcareous nodules, sand andsilt seams and partings, scattered gravel, and ferrous
staining. CH (Pecan Gap)

673.5
3.5

P=4.5+- gravel layer at 7 ft
P=4.5+
P=4.5+BALCONES_STD_25FT 0118-002 PLUM CREEK.GPJ 0118-002 PLUM CREEK.GPJ 06/05/18 11:46

10

667.0
10.0

P=4.5+

15

NOTES:
1. Boring was advanced dry to the 10-ft depth, and no
groundwater was encountered.
2. Soil samples were obtained using direct-pushgeoprobe and auger cuttings.
3. Bulk samples from auger cuttings were obtained
from 0-3 ft and 5-10 ft.

20

Balcones
Geotechnical
Austin, TX 78731
512.380.9969

COMPLETION DEPTH: 10.0

KEY:

DATE DRILLED: 1-25-18
WATER LEVEL / SEEPAGE: Not Observed

P = Pocket Penetrometer
N = Standard Penetration Test (bpf)
U = Unconfined Compression (tsf)

UPON COMPLETION: Not Observed
0

Plate 13

LOG OF BORING NO. B-155
Plum Creek FRS No. 10
Buda, Texas

P=0.75P=0.25

UNIT DRYWEIGHT, PCF

PASSING NO.
200 SIEVE, %UNCONFINEDSTRENGTH
TSF

SURF. ELEVATION: 672±

PASSING NO.4
SIEVE, %LAYER
ELEV./
DEPTH

PLASTICITYINDEX (PI), %STRATUM DESCRIPTIONLIQUID
LIMIT, %PROJECT NO. 0118-002
WATER
CONTENT, %POCKET PEN, tsf
Blows/ft.
REC./RQD, %SYMBOLSAMPLESDEPTH, FT

LATTITUDE: 30.063236
LONGITUDE: -97.802423

Dark grayish brown FAT CLAY, soft to firm,
w/calcareous nodules, sand, scattered organics, andtrace gravel. CH

P=1.0
P=1.0

5

P=1.25

Brownish gray FAT CLAY, stiff, w/calcareous nodules,
sand, gravel, and ferrous staining. CH

667.5
4.5

P=1.25- gravel at 6 ft
P=2.75
P=1.5
P=3.5

BALCONES_STD_25FT 0118-002 PLUM CREEK.GPJ 0118-002 PLUM CREEK.GPJ 06/05/18 11:46

10

Tan and gray FAT CLAY, stiff to hard, slightly blocky,
calcareous, w/calcareous nodules, sand and silt
seams and partings, scattered gravel, and ferrous
staining. CH (Pecan Gap)

662.0
10.0

P=4.5+

15

665.5
6.5

NOTES:
1. Boring was advanced dry to the 10-ft depth, and no
groundwater was encountered.
2. Soil samples were obtained using direct-pushgeoprobe and auger cuttings.
3. Bulk samples from auger cuttings were obtained
from 0-4 ft, 4-6.5 ft, and 6.5-10 ft.

20

Balcones
Geotechnical
Austin, TX 78731
512.380.9969

COMPLETION DEPTH: 10.0

KEY:

DATE DRILLED: 1-25-18
WATER LEVEL / SEEPAGE: Not Observed

P = Pocket Penetrometer
N = Standard Penetration Test (bpf)
U = Unconfined Compression (tsf)

UPON COMPLETION: Not Observed
0

Plate 14

LOG OF BORING NO. B-156
Plum Creek FRS No. 10
Buda, Texas

P=1.5
P=4.5+
P=4.5+
P=4.5+

5

P=4.5+UNIT DRYWEIGHT, PCF

PASSING NO.
200 SIEVE, %UNCONFINEDSTRENGTH
TSF

SURF. ELEVATION: 672±

PASSING NO.4
SIEVE, %LAYER
ELEV./
DEPTH

PLASTICITYINDEX (PI), %STRATUM DESCRIPTIONLIQUID
LIMIT, %PROJECT NO. 0118-002
WATER
CONTENT, %POCKET PEN, tsf
Blows/ft.
REC./RQD, %SYMBOLSAMPLESDEPTH, FT

LATTITUDE: 30.064094
LONGITUDE: -97.802874

Dark grayish brown FAT CLAY, stiff to hard,
w/calcareous nodules, sand, scattered organics, andtrace gravel. CH
Tan and gray FAT CLAY, very stiff to hard, slightly
blocky, calcareous, w/calcareous nodules, sand andsilt seams and partings, scattered gravel, and ferrous
staining. CH (Pecan Gap)
- gravel at 4 ft

669.5
2.5

P=3.25P=3.25
P=4.5
P=4.5+BALCONES_STD_25FT 0118-002 PLUM CREEK.GPJ 0118-002 PLUM CREEK.GPJ 06/05/18 11:46

10

662.0
10.0

P=4.5+

15

NOTES:
1. Boring was advanced dry to the 10-ft depth, and no
groundwater was encountered.
2. Soil samples were obtained using direct-pushgeoprobe and auger cuttings.
3. Bulk samples from auger cuttings were obtained
from 2.5-5 ft and 5-10 ft.

20

Balcones
Geotechnical
Austin, TX 78731
512.380.9969

COMPLETION DEPTH: 10.0

KEY:

DATE DRILLED: 1-25-18
WATER LEVEL / SEEPAGE: Not Observed

P = Pocket Penetrometer
N = Standard Penetration Test (bpf)
U = Unconfined Compression (tsf)

UPON COMPLETION: Not Observed
0

Plate 15

TERMS AND SYMBOLS USED ON BORING LOGS FOR SOIL
SOIL TYPES
CLAY (CH)SHALY CLAY (CH)

CLAY (CL)SANDY CLAY (CL)

Well-Graded
SAND (SW)

Poorly-Graded
SAND (SP)SILTY SAND (SM)

CLAYEY SAND (SC)

Well-Graded
GRAVEL (GW)

Poorly-Graded
GRAVEL (GP)SILTY GRAVEL (GM)FILL
Material

SOIL GRAIN SIZE
U.S.STANDARD SIEVE

12"

10
40
200
3/4"
4
GRAVELSAND
BOULDERS COBBLESCOARSE
FINE
FINE
COARSE MEDIUM
0.420
304
76.2
19.1
2.00
0.074
4.76
3"

SILT

CLAY
0.002

SOIL GRAIN SIZE IN MILIMETERS(2)

STRENGTH OF COHESIVE SOILS(2)

DENSITY OF GRANULAR SOILSCONSISTENCYUNDRAINEDCOMPRESSIVE STRENGTH
Tons Per Sq. Ft.

NUMBER OF BLOWSPER FT., N

RELATIVE
DENSITY

Very SoftLess Than 0.25

0-4

Very LooseSoft

0.25 to 0.50

4-10

Loose

Firm

0.5 to 1.00

10-30

MediumStiff

1.00 to 2.00

30-50

Dense

Very Stiff

2.00 to 4.00

Over 50

Very Dense

Hard

greater than 4.00

DESCRIPTIVE TERMS FOR SOIL (1)DESCRIPTION
Stratified

Laminated

Fissured

CRITERIA

MOISTURE

Alternating layers of varying
material or color with layers
at least 6 mm thick.

Dry

Alternating layers of varying
material or color with thelayers less than 6 mm thick.

Very Moist

Breaks along definite planes offracture with little resistanceto fracturing.

Slickensided

Fracture planes appear polishedor glossy, sometimes striated.

BlockyCohesive soil that can be broken
down into small angular lumps
which resist further breakdown.

LensedInclusions of small pockets ofdifferent soils.

Moist

Wet

No water evident in sample; fines lessthan plastic limit.
Sample feels damp; fines near the plastic
limit
Water visible on sample; fines greater
plastic limit and less than liquid limit
Sample bears free water; fines greaterthan liquid limit.
INCLUSIONS

Parting
Seam
Layer
Trace
Few
LittleWith(1)

Inclusion <1/8" thick extending throughsampleInclusion 1/8" to 3" thick extending
through sample.
Inclusion >3" thick extending throughsample.
<5% of sample.
5% to 10% of sample.
15 to 25% of sample.
15% to 29% of sample.

NOTE: Information on each boring log is a compilation of subsurface conditions and soil and rock classifications obtained
from the field as well as from laboratory testing of samples. Strata have been interpreted from commonly accepted
procedures. The stratum lines on the logs may be transitional and approximate in nature. Water levelmeasurements refer only to those observed at the times and places indicated, and may vary with time, geologic
condition or construction activity.
REFERENCES:

1) ASTM D 2488

2) Peck, Hanson and Thornburn, (1974), Foundation Engineering.

PLATE 16

TERMS AND SYMBOLS USED ON BORING LOGS FOR ROCKROCK TYPESSAMPLER TYPESLIMESTONESHALESANDSTONE

Thinwalled
Tube

Rock
Core

WEATHEREDLIMESTONE

WEATHEREDSHALE

WEATHEREDSANDSTONE

Standard
Penetration
Test

Auger
SampleHIGHLY WEATHEREDLIMESTONE

ARGILLACEOUS
LIMESTONEMARLTHD Cone
Penetration
Test

Bag
SampleWEATHERING GRADES OF ROCKMASS(1)SOLUTION & VOID CONDITIONSVoidInterstice; a general term for porespace or other openings in rock.

Cavities

Small solutional concavities.

Vuggy

Containing small cavities, usually
lined with a mineral of different
composition from that of thesurrounding rock.

Vesicular

Containing numerous small, unlined
cavities, formed by expansion of gas
bubbles or steam during solidificationof the rock.

PorousContaining pore, interstices, orother openings which may or may notinterconnect.

Cavernous

Containing cavities or caverns,
sometimes quite large. Most frequentin limestones and dolomites.

Slightly

Discoloration indicates
weathering of rock material
and discontinuity surfaces.

Moderately

Less than half of the rockmaterial is decomposed ordisintegrated to a soil.

HighlyMore than half of the rockmaterial is decomposed ordisintegrated to a soil.

Completely

All rock material isdecomposed and/or
disintegrated to soil.The
original mass structure is
still largely intact.

Residual SoilAll rock material isconverted to soil.The
mass structure and material
fabric are destroyed.

BEDDING THICKNESS (2)HARDNESSFriableLow Hardness
Moderately Hard
Very Hard

Very Thick
Thick
Thin
Very Thin
Laminated
Thinly-LaminatedCrumbles under hand pressure
Can be carved with a knife
Can be scratched easily with a knife
Cannot be scratched with a knife

>4'
2'-4'
2"-2'
1/2"-2"0.08"-1/2"<0.08"JOINT DESCRIPTIONSPACING
Very Close
Close
Medium CloseWide

INCLINATION<2"2"-12"
12"-3'>3'

Horizontal
Shallow
Moderate
Steep
Vertical

0-5
5-35
35-65
65-85
85-90

SURFACES
Slickensided
SmoothIrregular
Rough

Polished, grooved
PlanarUndulating or granular
Jagged or pitted

NOTE: Information on each boring log is a compilation of subsurface conditions and soil and rock classificaitonsobtained from the field as well as from laboratory testing of samples. Strata have been interpreted by commonly
accepted procedures. The stratum lines on the logs may be transitional and approximate in nature. Water levelmeasurements refer only to those observed at the times and places indicated, and may vary with time, geologic
condition or construction activity.
REFERENCES: 1) British Standard(1981) Code of Practice for Site Investigation

BS 5930.
2) The Bridge Division, Texas Highway Dept. Foundation Exploration & Design Manual,
2nd Edition,revised June,1974.

PLATE 17

APPENDIX D
Laboratory TestingU.S. SIEVE OPENING IN INCHES
6

100

4

3

2

1.5

1

3/4

U.S. SIEVE NUMBERS
1/2

3/8

3

4

6

8

10

14

16

20

30

40

50

HYDROMETER
60

100

140

200

95
90
85
80
75

PERCENT FINER BY WEIGHT

70
65
60
55
50
45
40
35
30
25
20
15
10
5
0

100

10

1

0.1

0.01

0.001

GRAIN SIZE IN MILLIMETERSGRAINSIZE.GPJ 4/27/18 (GRAIN SIZE BG,US_LAB.GDT,LIBRARY2013-01.GLB)

COBBLESGRAVELcoarsefine

SAND
coarsemediumfine

Classification
FAT CLAY with SAND (CH)FAT CLAY (CH)SANDY FAT CLAY (CH)FAT CLAY with SAND (CH)SILT OR CLAY

Boring Elev
B-301
B-301
B-601
B-602

Depth
19.0
34.0
6.0
2.0

Boring
B-301
B-301
B-601
B-602

%Gravel %Sand
%Silt
%Clay
Depth
D30
D10
D100
D60
19.0
4.75
14.0
84.0
34.0
4.75
0.0
14.0
86.0
6.0
4.75
0.177
0.009
0.0
46.0
33.4
20.6
2.0
4.75
0.0
21.0
79.0
Silt and clay fractions were determined using 0.002 mm as the maximum particle size for clay.

LL
57
69
61
77

PL
24
24
20
27

PI
33
45
41
50

Cc

GRAIN SIZE DISTRIBUTION
Project: Plum Creek FRS No. 10
Location: Buda, TX
Job No.: 0118-002

CuU.S. SIEVE OPENING IN INCHES
6

100

4

3

2

1.5

1

3/4

U.S. SIEVE NUMBERS
1/2

3/8

3

4

6

8

10

14

16

20

30

40

50

HYDROMETER
60

100

140

200

95
90
85
80
75

PERCENT FINER BY WEIGHT

70
65
60
55
50
45
40
35
30
25
20
15
10
5
0

100

10

1

0.1

0.01

0.001

GRAIN SIZE IN MILLIMETERSGRAINSIZE.GPJ 4/27/18 (GRAIN SIZE BG,US_LAB.GDT,LIBRARY2013-01.GLB)

COBBLESGRAVELcoarsefine

SAND
coarsemediumfine

Classification
FAT CLAY with SAND (CH)FAT CLAY with SAND (CH)FAT CLAY with SAND (CH)FAT CLAY with SAND (CH)SILT OR CLAY

Boring Elev
B-603
B-603
B-604
B-605

Depth
8.0
11.0
6.0
2.0

Boring
B-603
B-603
B-604
B-605

%Gravel %Sand
%Silt
%Clay
Depth
D30
D10
D100
D60
45.0
8.0
9.51
0.017
2.0
25.0
28.0
11.0
4.75
0.0
15.0
85.0
6.0
9.51
0.017
2.0
25.0
29.1
43.9
2.0
4.75
0.0
20.0
80.0
Silt and clay fractions were determined using 0.002 mm as the maximum particle size for clay.

LL
50
60
53
66

PL
15
21
18
25

PI
35
39
35
41

Cc

GRAIN SIZE DISTRIBUTION
Project: Plum Creek FRS No. 10
Location: Buda, TX
Job No.: 0118-002

CuU.S. SIEVE OPENING IN INCHES
6

100

4

3

2

1.5

1

3/4

U.S. SIEVE NUMBERS
1/2

3/8

3

4

6

8

10

14

16

20

30

40

50

HYDROMETER
60

100

140

200

95
90
85
80
75

PERCENT FINER BY WEIGHT

70
65
60
55
50
45
40
35
30
25
20
15
10
5
0

100

10

1

0.1

0.01

0.001

GRAIN SIZE IN MILLIMETERSGRAINSIZE.GPJ 4/27/18 (GRAIN SIZE BG,US_LAB.GDT,LIBRARY2013-01.GLB)

COBBLESGRAVELcoarsefine

SAND
coarsemediumfine

Classification
FAT CLAY with SAND (CH)FAT CLAY with SAND (CH)FAT CLAY with SAND (CH)FAT CLAY with SAND (CH)SILT OR CLAY

Boring Elev
B-605
B-606
B-606
B-607

Depth
10.0
2.0
10.0
2.0

Boring
B-605
B-606
B-606
B-607

%Gravel %Sand
%Silt
%Clay
Depth
D30
D10
D100
D60
50.2
10.0
9.51
0.011
1.0
20.0
28.8
2.0
9.51
6.0
10.0
84.0
10.0
4.75
0.0
21.0
79.0
2.0
4.75
0.0
18.0
82.0
Silt and clay fractions were determined using 0.002 mm as the maximum particle size for clay.

LL
74
72
50
66

PL
25
24
19
24

PI
49
48
31
42

Cc

GRAIN SIZE DISTRIBUTION
Project: Plum Creek FRS No. 10
Location: Buda, TX
Job No.: 0118-002

CuFugro USA Land, Inc.
8613 Cross Park Drive
Austin, Texas 78754
Phone (512) 977-1800

LABORATORY TEST REPORT

Project: Balcones Geotechnical
Project Number: 04.30182002

Date Assigned: 2/21/18

Assigned By: R.Russo

Client Project & No.: Plum Creek 0118-002
Report Date:03/21/2018
Percent
Percent
Boring Depth (Feet) Moisture Liquid Plastic Plasticity Percent Percent Percent Percent Percent
in %
Limit
Limit
Index
Passing Passing Passing Passing
Passing
Passing
Passing
(3/8)
(#4)
(#10)
(#40)
(-200)
0.074
0.005

Percent
Passing
0.001

B601

6-8

25.71

61

20

41

100.0

100.0

94.4

66.0

53.6

B602

2-4

38.79

77

50

27

100.0

100.0

99.6

92.8

79.4

B603

8-9

15.82

50

15

35

100.0

98.2

95.0

85.6

73.3

B603

11-12

22.31

60

21

39

100.0

100.0

99.8

98.2

84.6

B604

6-8

19.69

53

18

35

100.0

98.3

96.8

85.8

73.0

B605

2-4

23.96

66

25

41

100.0

100.0

99.6

92.4

80.1

B605

10-11

29.05

74

25

49

100.0

99.5

99.5

94.1

78.1

B606

2-4

27.59

72

24

48

100.0

94.1

94.1

90.0

83.6

B606

10-12

23.93

47

19

28

100.0

100.0

99.8

97.2

78.9

B607

2-4

28.55

66

24

42

99.0

93.9

81.6

B301

19-20

22.66

57

24

33

98.4

91.7

83.7

B301

34-35

24.76

69

24

45

100.0

95.1

85.5

CS1

No Lime

81

30

51

99.7

97.9

95.4

CS1

4% Lime

68

53

15

12.5

CS1

5% Lime

70

56

14

12.6

CS1

6% Lime

69

55

14

12.6

CS2

No Lime

55

19

36

CS2

4% Lime

52

35

17

12.6

CS2

5% Lime

53

36

17

12.7

CS2

6% Lime

55

38

17

12.7

S3

--

20.54

85

21

64

99.9

98.5

96.3

S4

--

11.02

58

22

36

98.9

97.6

93.7

96.1

92.4

86.7

53.5

24.4

17.7

73.2

48.8

41.7

72.9

49.1

39.8

78.8

53.1

48.1

TEX-121 and Tex128

8.2

8.6

peak stress ratio (from TRI lab datasheet)σ 3' fMinor Effective Stresspsi
Principal Stress Difference (σ1 - σ3)f
psi

2

7.1

13

10.5

17.1

24.1

Pore Water Pressure

Δuf

psi

3

7

10.1

Major Effective Stressp' at failure where p' = ( σ1'f + σ3'f ) / 2

σ 1' f

psi

12.5

24.2

37.1

p'f

psi

7.25

15.65 25.05

10.25 22.65 35.15

p at failure where p = ( σ1f + σ3f ) / 2

pf

psi

q at failure where q = ( σ1f - σ3f ) / 2
Effective Stress Cohesion (CD Conditions)
Effective Stress Friction Angle (CD Conditions)
Total Stress Cohesion (CU Conditions)
Total Stress Friction Angle (CU Conditions)

qf
c'
ϕ'
c
ϕ

psi
psi
degreespsi
degrees

5.25

peak stress difference (from TRI lab datasheet)σ 3' fMinor Effective Stresspsi
7.1
Principal Stress Difference (σ1 - σ3)f
psi
18.2

8.55 12.05
2.720
22.4472.518
15.849

9.4

16.9

19.2

26.3

Pore Water Pressure

Δuf

psi

-2.2

4.7

6.2

Major Effective Stressp' at failure where p' = ( σ1'f + σ3'f ) / 2

σ 1' f

psi

25.3

28.6

43.2

p'f

psi

16.2

19

30.05

p at failure where p = ( σ1f + σ3f ) / 2

pf

psi

14

23.7

36.25

q at failure where q = ( σ1f - σ3f ) / 2
Effective Stress Cohesion (CD Conditions)
Effective Stress Friction Angle (CD Conditions)
Total Stress Cohesion (CU Conditions)
Total Stress Friction Angle (CU Conditions)

qf
c'
ϕ'
c
ϕ

psi
psi
degreespsi
degrees

9.1

9.6 13.15
4.277
17.493
6.118
10.769Peak Stress Ratio (s1/s3)max
14

y = 0.3818x + 2.5137
R² = 0.9998

12

y = 0.2731x + 2.4218
R² = 0.9998

10

8

6

4

2

0
0

5

10

15

20

25

30

35

40

Peak Stress Difference (s'1-s'3)max
14

y = 0.3006x + 4.0788
R² = 0.9938

12

y = 0.1869x + 6.0107
R² = 0.8911

10
8
6
4
2
0
0

5

10

15

20

25

30

35

40

Consolidated-Undrained Triaxial Compression
Client: Balcones Geotechnical
Project: Plum Creek
Sample: 30.18 (18 - 19)

TRI Log #:Test Method:

Specimens

Test Setup

Identification
Depth/Elev. (ft)Eff. Consol. Stress (psi)5.0
15.0
Initial Specimen Properties
Avg. Diameter (in)
1.42
1.41
Avg. Height (in)
3.14
3.00
Avg. Water Content (%)
25.5
23.9
Bulk Density (pcf)
116.6
114.7
Dry Density (pcf)
93.0
92.6
Saturation (%)
Void Ratio, nSpecific Gravity (Assumed)
Total Back-Pressure (psi)B-Value, End of Saturation

84.5
0.81
2.70
54.3
0.95

35589
ASTM D4767

78.6
0.82
2.70
55.1
1.00

Failure Criterion: Peak Principal Stress

25.0

Specimen Condition

Undisturbed / Intact

Specimen Preparation

Trimmed

1.41
3.28
25.9
119.5
94.9

Mounting Method
Consolidation

Wet
Isotropic

90.2
0.78
2.70
56.0
1.00

2

Void Ratio

Post-Consolidation / Pre-Shear
0.81
0.78

Area (in )

0.74

1.57

1.55

1.53

Shear / Post-Shear
Avg. Water Content (%)
28.0
Rate of Strain (%/hr)
0.50

29.3
0.50

25.3
5.00

At Failure
Difference, (s1'-s3')max

Ratio, (s1'/s3')max

Axial Strain at Failure (%), ea,f

15.0

15.0

15.0

1.1

3.8

5.7

Minor Effective Stress (psi), s3'f
Principal Stress Difference (psi), (s1-s3)f

7.1
18.2

9.4
19.2

16.9
26.3

2.0
10.5

7.1
17.1

13.0
24.1

Pore Water Pressure, Duf (psi)

-2.2

4.7

6.2

3.0

7.0

10.1

Major Effective Stress (psi), s1'f
Secant Friction Angle (degrees)
Effective Friction Angle (degrees)
Effective Cohesion (psi)

25.3
34.1

28.6
30.4
17.5
4.3

43.2
25.9

12.4
46.7

24.2
33.2
22.4
2.7

37.2
28.7

Please note that the presented M-C parameters are based on a linear regression in modified stress space, across all assigned
effective consolidation stresses. This fit does not purported to capture typical curvature of envelopes that may, in particular, beobserved across broader range in effective stresses. Please note that the stresses associated with peak principal stress ratio andpeak principal stress difference are presented in tabular form on the first page of the report. There are alternate interpretations totheses two failure criterion including but not limited to strain compatibility and post-peak.

Jeffrey A. Kuhn , Ph.D., P.E., 3/19/2018
Analysis & Quality Review/Date

1 of 5

Consolidated-Undrained Triaxial Compression
Client: Balcones Geotechnical
Project: Plum Creek
Sample: 30.18 (18 - 19)

TRI Log #:Test Method:

35589
ASTM D4767

Modified Mohr-Coulomb
60

5 psi
15 psi25 psiPeak Principal Stress Difference

50

Peak Principal Stress Ratio
Linear (Peak Principal Stress Difference)Linear (Peak Principal Stress Ratio)

40

Principal Stress
Difference,30

s1' - s3' (psi)
20

10

0

0

5

10

15

20

25

30

Minor Principal Effective Stress , s3'(psi)

Failure Criterion: Peak Principal Stress
Effective Friction Angle (deg)
Effective Cohesion (psi)

Difference, (s1'-s3')max
17.5
4.3

2 of 5

Ratio, (s1'/s3')max
22.4
2.7

Consolidated-Undrained Triaxial Compression
Client: Balcones Geotechnical
Project: Plum Creek
Sample: 30.18 (18 - 19)

TRI Log #:Test Method:

35589
ASTM D4767

Mohr-Coulomb
50
Failure Criterion
Peak Principal Stress Difference

Peak Principal Stress Ratio
40

30

Shear Stress,t (psi)
20

10

0
0

10

20

30

40

50

Effective Stress, s'(psi)

Failure Criterion: Peak Principal Stress
Effective Friction Angle (deg)
Effective Cohesion (psi)

Difference, (s1'-s3')max
17.5
4.3

3 of 535

Ratio, (s1'/s3')max
22.4
2.7

Consolidated-Undrained Triaxial Compression
Client: Balcones Geotechnical
Project: Plum Creek
Sample: 30.18 (18 - 19)

TRI Log #:Test Method:

35589
ASTM D4767

35

5 psi

30

Principal

StressDifference,s1' - s3' (psi)

15 psi25 psiPeak Principal Stress Difference

Peak Principal Stress Ratio

25
20
15
10
5
0
0.0

2.5

5.0

7.5

10.0

12.5

15.0

17.5

20.0

22.5

0.0

2.5

5.0

7.5

10.0

12.5

15.0

17.5

20.0

22.5

0.0

2.5

5.0

7.5

10.0

12.5

15.0

17.5

20.0

22.5

0.0

2.5

5.0

7.5

10.0

12.5

15.0

17.5

20.0

22.5

7
6

Principal

5

Stress Ratio,4s1' / s3'

3
2
1

15

10

Change inPore Pressure,5

Du (psi)
0

-5

1.00
0.75
0.50

A

0.25
0.00
-0.25
-0.50

Axial Strain, ea (%)

4 of 5

Consolidated-Undrained Triaxial Compression
Client: Balcones Geotechnical
Project: Plum Creek
Sample: 30.18 (18 - 19)

TRI Log #:Test Method:

35589
ASTM D4767

Consolidation
5 psi

0.05

0.1
0.15
0.1

1
10
Time (minutes)

0.1
0.15
0

2.5
5
7.5
Root Time (square root of minutes)

0.5
1

1.5
2

0.5
1
1.5

2
0.1

1

10
100
Time (minutes)

1000

10000

0

10
20
30
Root Time (square root of minutes)

25 psi
0
0.25
0.5
0.75
1
1.25
1.5
1.75
2
0.1

1

10

40

25 psi
Volume Change (ml)Volume Change (ml)1015 psi0Volume Change (ml)Volume Change (ml)

0.05

100

15 psi05 psi

0Volume Change (ml)Volume Change (ml)

0

100

1000

10000

0
0.25
0.5
0.75
1
1.25
1.5
1.75
2
0

Time (minutes)

10

20

30

Root Time (square root of minutes)

5 of 540

APPENDIX ESLIDE Slope Stability Computer Output

CU and CD Strength Envelopes
CU
CD
c
phi
c'
phi'
400
10.8
200
17.5

Simple 3-Point Envelope
Normal
0
1606
8000

CU
400
706
1926

CD
200
706
2722

Normal US RDD Normal
0
200
0
1606
706
1606
8000
1926
8000

DS SSS
200
706
2324

3000
2500
2000
1500
1000
500
0
0

1000

2000

3000

4000

CU

5000
CD

6000

7000

8000

9000

US RDD

3000
2500
2000
1500
1000
500
0
0

1000

2000

3000
CU

4000

5000
CD

6000
DS SSS

7000

8000

9000

Normal
2000
0
1800
25
1600
50
1400
75
1200
100
125
1000
150
800
175
600
200
400
225
200
250
0
275
300 0
325
350
2000
375
1800
400
1600
425
1400
450
1200
475
500
1000
525
800
550
600
575
400
600
200
625
0
650
675 0

CU
400
405
410
414
419
424
429
433
438
443
448
452
457 1000
462
467
472
476
481
486
491
495
500
505
510
514
519
524
529 1000Shear vs Normal in 25psf Increments
US RDDDS SSSCD(CU+CD)/2 Normal
Shear
Normal
Shear
200
300
0
200
0
200
208
306
25
208
25
208
216
313
50
216
50
216
224
319
75
224
75
224
232
325
100
232
100
232
239
332
125
239
125
239
247
338
150
247
150
247
255
344
175
255
175
255
263
351
200
263
200
263
271
357
225
271
225
271
279
363
250
279
250
279
287
370
275
287
275
287
295 2000 376 3000 300 4000 295 5000 300 6000 295
302
382
325
302
325
302
310
389
350
310
350
310
318
395
375
318
375
318
326
401
400
326
400
326
334
408
425
334
425
334
342
414
450
342
450
342
350
420
475
350
475
350
358
427
500
358
500
358
366
433
525
366
525
366
373
439
550
373
550
373
381
445
575
381
575
381
389
452
600
389
600
389
397
458
625
397
625
397
405
464
650
405
650
405
2000
3000
4000
5000
6000
413
471
675
413
675
413

US RDDCUCD

DS SSS
CU
CD

760
740

Safety Factor
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
4.00
4.50
5.00
5.50
6.00+

Unit Weight(lbs/ft3)

Strength Type

Natural Soil

120

Mohr-Coulomb

Existing Dam / Subgrade

115

Shear Normal
function

Compacted Earthfill

120

Mohr-Coulomb

150

Rock Riprap

120

Mohr-Coulomb

Lime Treated Earthfill

120

Topsoil

120

Material Name

Color Model

0

0

0

20

0

0

0

40

0

0

Mohr-Coulomb

150

24

0

0

Mohr-Coulomb

150

28

0

0

KS (ft/min) K2/K1

200

26

1.60

Air Entry(psf)

K1 Angle
Soil Type(deg)

Natural Soil

Simple1e-0070.25

0GeneralExisting Dam / Subgrade

Simple1e-0070.25

0GeneralCompacted Earthfill

Simple1e-0070.25

0GeneralRock Riprap

Simple1e-0030.25

0GeneralLime Treated Earthfill

Simple1e-006

0.25

0GeneralTopsoil

Simple1e-0070.25

0GeneralToe Drain

Simple1e-0040.25

0General

640

660

680

700

Cohesion Phi Phi b(psf)(deg) (deg)0720Material Name

Color

Total Head[ft]655.500
658.500
661.500
664.500
667.500
670.500
673.500
676.500
679.500
682.500
685.500
688.500

-100

-80

-60

-40

-20

0

20

40

60

80

100

120

740

Total Head[ft]654.000
657.000
660.000
663.000
666.000
669.000
672.000
675.000
678.000
681.000
684.000
687.000
690.000

Color Model

KS (ft/min) K2/K1

K1 Angle
Soil Type(deg)

Natural Soil

Simple1e-0070.25

0GeneralExisting Dam / Subgrade

Simple1e-0070.25

0GeneralCompacted Earthfill

Simple1e-0070.25

0GeneralRock Riprap

Simple1e-0030.25

0GeneralLime Treated Earthfill

Simple1e-006

0.25

0GeneralTopsoil

Simple1e-0070.25

0GeneralToe Drain

Simple1e-0040.25

0General

630

640

650

660

670

680

690

700

710

720

730

Material Name

-100

-80

-60

-40

-20

0

20

40

60

80

100

120

740

Total
Hydraulic Gradient
0.000
0.140
0.280
0.420
0.560
0.700
0.840
0.980
1.120
1.260
1.400
1.540
1.680

Color Model

KS (ft/min) K2/K1

K1 Angle
Soil Type(deg)

Natural Soil

Simple1e-0070.25

0GeneralExisting Dam / Subgrade

Simple1e-0070.25

0GeneralCompacted Earthfill

Simple1e-0070.25

0GeneralRock Riprap

Simple1e-0030.25

0GeneralLime Treated Earthfill

Simple1e-006

0.25

0GeneralTopsoil

Simple1e-0070.25

0GeneralToe Drain

Simple1e-0040.25

0General

630

640

650

660

670

680

690

700

710

720

730

Material Name

-100

-80

-60

-40

-20

0

20

40

60

80

100

120

Slide Analysis Information
SLIDE - An Interactive Slope Stability Program
Project Summary• File Name: Section Station 12• Slide Modeler Version: 6.039• Project Title: SLIDE - An Interactive Slope Stability Program• Date Created: 3/29/2018, 4:22:35 PM

General Settings• Units of Measurement: Imperial Units• Time Units: days
• Permeability Units: feet/minute• Failure Direction: Left to Right• Data Output: Standard• Maximum Material Properties: 20• Maximum Support Properties: 20

Analysis Options
Analysis Methods Used
• Spencer• Number of slices: 25• Tolerance: 0.005• Maximum number of iterations: 50• Check malpha < 0.2: Yes• Initial trial value of FS: 1• Steffensen Iteration: Yes

Groundwater Analysis• Groundwater Method: Steady State FEA• Pore Fluid Unit Weight: 62.4 lbs/ft3• Tolerance: 1e-006• Maximum number of iterations: 500• Advanced Groundwater Method: None
• Mesh Element Type: 3 noded triangles• Number of Elements: 4233
• Number of Nodes: 2226

Random Numbers• Pseudo-random Seed: 10116• Random Number Generation Method: Park and Miller v.3

Surface Options• Search Method: Auto Refine Search• Divisions along slope: 15• Circles per division: 15• Number of iterations: 10

• Divisions to use in next iteration: 50%• Number of vertices per surface: 12• Minimum Elevation: Not Defined• Minimum Depth: Not DefinedMaterial Properties
Property

Natural Soil

Existing Dam /Subgrade

Compacted
Earthfill

Rock Riprap

Lime Treated
Earthfill

___

___

___

___

___

___

___

MohrCoulomb
120
200
26

Shear Normal
function
115

MohrCoulomb
120
150
20

MohrCoulomb
120
0
40

MohrCoulomb
120
150
24

MohrCoulomb
120
150
28

MohrCoulomb
120
0
32

0

0

0

0

0

0

0

0
1e-0070.25
0SimpleSoil Type:
General0
1e-0070.25
0SimpleSoil Type:
General0
1e-0070.25
0SimpleSoil Type:
General0
1e-0030.25
0SimpleSoil Type:
General0
1e-0060.25
0SimpleSoil Type:
General0
1e-0070.25
0SimpleSoil Type:
General0
1e-0040.25
0SimpleSoil Type:
GeneralColorStrength Type
Unit Weight [lbs/ft3]
Cohesion [psf]Friction Angle [deg]Unsaturated Shear
Strength Angle [deg]Air Entry Value [psf]Ks [feet/minute]
K2/K1
K Angle [deg]Groundwater Model
GW Model Properties

Shear Normal Functions•

Name: DS SSS
Normal (psf) Shear (psf)
0
200
1606
706
8000
2324

Global Minimums
Method: spencer
•
•
•
•
•
•
•
•
•

FS: 1.598920
Axis Location: 64.014, 764.061
Left Slip Surface Endpoint: -6.216, 685.600
Right Slip Surface Endpoint: 84.645, 660.800
Resisting Moment=6.3842e+006 lb-ft
Driving Moment=3.99281e+006 lb-ft
Resisting Horizontal Force=52940.3 lb
Driving Horizontal Force=33109.9 lb
Total Slice Area=1256.9 ft2

Global Minimum Coordinates
Method: spencer
XY-6.21605
685.6
4.28487 674.123

TopsoilToe Drain

10.4227 668.363
17.6719 663.198
25.9869 658.867
34.2461 656.059
42.6887 654.39
52.3516653.8
62.3555 653.709
71.0976 655.064
79.0197 657.821
84.6449660.8

Valid / Invalid Surfaces
Method: spencer••

Number of Valid Surfaces: 6701
Number of Invalid Surfaces: 9050
Error Codes:
o Error Code -105 reported for 2695 surfaceso Error Code -106 reported for 2535 surfaceso Error Code -108 reported for 3810 surfaceso Error Code -1000 reported for 10 surfaces
Error Codes
The following errors were encountered during the computation:o -105 = More than two surface / slope intersections with no valid slip surface.
o -106 = Average slice width is less than 0.0001 * (maximum horizontal extent of soil region). This limitation is
imposed to avoid numerical errors which may result from too many slices, or too small a slip region.
o -108 = Total driving moment or total driving force < 0.1. This is to limit the calculation of extremely high safety
factors if the driving force is very small (0.1 is an arbitrary number).
o -1000 = No valid slip surfaces are generated at a grid center. Unable to draw a surface.

Slice Data
• Global Minimum Query (spencer) - Safety Factor: 1.59892
Slice
NumberWidth[ft]

Weight[lbs]

1 0.914921 54.8953
2

2.74476 823.429

33.42062 2377.25

43.42062 3847.94

5

3.06893 4622.86

6

3.06893 5426.84

73.62459 7084.97

BaseMaterial
Topsoil
Lime Treated
Earthfill
Existing Dam /Subgrade
Existing Dam /Subgrade
Existing Dam /Subgrade
Existing Dam /Subgrade
Existing Dam /Subgrade

Base
Cohesion
[psf]

Base
FrictionAngle[degrees]

Shear
Shear
Stress Strength
[psf]
[psf]

Base
NormalStress[psf]

PorePressure[psf]

670.199147.079557.858
415.363387.802-14.5588

Effective
NormalStress[psf]

150

28 88.9719 142.259-14.5588

150

24 134.768 215.484

200

17.488 206.932 330.868

200

17.488 267.054 426.998

720.474-220.39720.474200

17.488 332.498 531.637

1052.59

71.40211052.59200

17.488 361.399 577.848

1253.01 53.7537

1199.26200

17.488 392.467 627.523

1524.96 168.042

1356.92

147.079415.36383.62459 7660.05

94.15751 9304.05

10

4.1575111

4.12958 9809.46

12

4.12958 9825.32

13

4.2213114

4.22131 9639.55

15

4.83143 10512.1

164.83143 9785.24

17

3.33465 6296.56

18

3.33465 5883.81

19

3.33465 5471.13

20

4.37105 6368.55

21

4.37105 5301.92

22

6.13786 5181.25

23

1.78417 937.841

24

3.73704 1005.54

25

1.88819 113.292

9679.99914.3

Existing Dam /Subgrade
Existing Dam /Subgrade
Existing Dam /Subgrade
Existing Dam /Subgrade
Existing Dam /Subgrade
Existing Dam /Subgrade
Existing Dam /Subgrade
Existing Dam /Subgrade
Existing Dam /Subgrade
Existing Dam /Subgrade
Existing Dam /Subgrade
Existing Dam /Subgrade
Existing Dam /Subgrade
Existing Dam /Subgrade
Existing Dam /Subgrade
Compacted
Earthfill
Compacted
Earthfill
Topsoil200

17.488 398.288

636.831659.94 273.476

1386.46200

17.488 426.235 681.515

1894.59 366.301

1528.29200

17.488 426.519 681.969

1975.76 446.031

1529.73299.60214.2006 449.392 718.542

2160.99 505.423

1655.56299.60214.2006

444.04 709.985

2165.18 543.432

1621.75

299.60214.2006 455.713 728.648

2260.4 564.902

1695.5299.60214.2006 445.121 711.713

2197.8 569.221

1628.58

299.60214.2006 450.464 720.256

2216.44 554.111

1662.33200

17.488 429.621

686.932064.77 519.296

1545.47200

17.488 418.062 668.448

1971 484.188

1486.82200

17.488 399.996 639.561

1843.73 448.605

1395.13200

17.488 382.328 611.312

1716.56 411.096

1305.47200

17.488 383.354 612.952

1654.79 344.114

1310.68200

17.488 350.911 561.079

1389.84

243.811146.03200

17.488 328.854 525.811

1113.52 79.4226

1034.1150

20 259.213 414.461

726.601

102.949726.601150

20 201.658 322.435

473.761-81.324473.761150

28 161.624 258.424

203.915163.113203.915Interslice Data
• Global Minimum Query (spencer) - Safety Factor: 1.59892
X
YInterslice
Interslice
Interslice
Slicecoordinate coordinate - Bottom Normal Force Shear Force Force Angle
Number
[ft]
[ft]
[lbs]
[lbs]
[degrees]
1 -6.21605
685.6
0
0
0
2 -5.30113
684.6-95.9609-20.7563
12.205
3 -2.55637
681.6-24.6306-5.3276
12.205140.86425677.861820.454
177.464
12.20554.28487
674.123
2600.6562.50912.2056
7.3538671.243
4611.59
997.485
12.2057
10.4227668.363
7111.091538.13
12.2051814.0473665.789626.582082.23
12.2051917.6719663.198
12469.5
2697.15
12.205

10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26

21.829425.9869
30.1165
34.2461
38.4674
42.6887
47.520252.351655.686259.020962.3555
66.7266
71.0976
77.2355
79.0197
82.7567
84.6449

List Of Coordinates
External BoundaryXY
120 640
120 656.3
108.8 656.3
95.4 660.8
81.4 660.8
7 685.6-7 685.6-26.8014 679-41.8 674
-48.2 674
-57.1261 671-60.1 670
-65.8 670
-82.8 664.3-89.9 663
-91.1 662.9-100 662.4-100 657.9-100 640.1

Material BoundaryXY-82.8 664.3-57.2 669
-53.8 670
-41.8 674
-38.6 674

661.032658.867
657.463656.059655.225654.39654.095653.8
653.77653.74653.709654.387655.064657.2
657.821
659.8
660.8

14800.5
17306.1
18483.6
19689.1
19652.3
19607.918085.2
16618.5
15284
14005.8
12782.7
9986.017510.63
3113.93
2200.35
509.092
03201.34
3743.33998
4258.75
4250.784241.18
3911.833594.58
3305.923029.452764.892159.97
1624.55
673.541475.934
110.1160

12.20512.20512.20512.20512.20512.20512.2051
12.20512.20512.20512.20512.20512.2051
12.20512.20512.2050

-6.8 684.6
6.9 684.6
78.204 660.8
81.2 659.8
95.3 659.8
105.7 656.3
108.8 656.3

Material BoundaryXY-57.2 669
-42.8 669
-27.8 674
-5 681.6
5 681.6
61.5 660.8
70.4 657.2
78.6 657.2
81.4 657.2
85 657.2
100.6 657.2
105.7 656.3

Material BoundaryX
Y-60.1 670
-53.8 670

Material BoundaryX
Y-60.1 670
-60.1 669
-57.2 669

Material BoundaryX
Y-100 657.9-64.6 657.9
75.2 653
78.6 653
81.4 653
85 65385 657.2
90.4 655.5
111.2 655.5
113.7 656
120 656.3

Material Boundary

XY
61.5 660.8
78.204 660.8

Material BoundaryXY-38.6 674
-27.8 674

Material BoundaryXY
78.6 657.2
78.6 654.41
78.6
653
78.6
652
81.4
652
81.4
653
81.4 654.41
81.4 657.2

Rapid Drawdown(RD) UndrainedStrength

RD Envelope
Type

26

No

Total stress R
linear

200

17.5

Yes

Total stress R
linear400

Mohr-Coulomb

100

17.5

Yes

Total stress R
linear150

120

Mohr-Coulomb

0

40

No

Total stress R
linearLime Treated Earthfill

120

Mohr-Coulomb

50

17.5

Yes

Total stress R
linearTopsoil120

Mohr-Coulomb

0

28

No

Toe Drain120

Mohr-Coulomb

0

32

No

Unit Weight(lbs/ft3)

Strength Type

Natural Soil

120

Mohr-Coulomb

200

Existing Dam / Subgrade

115

Mohr-Coulomb

Compacted Earthfill120

Rock Riprap

Material Name

Color

Cohesion Phi
(psf)
(deg)

1.21

RD Cr
(psf)

RD PhiR(deg)

Water Surface Hu Type Hu

Water Surface Custom

1

10.8

Water Surface Custom

1

10.8

Water Surface Custom

1

Water Surface Custom

1

Water Surface Custom

1

Total stress R
linear

Water Surface Custom

1

Total stress R
linear

Water Surface Custom

1

100

10.8

740
680

700

720

Safety Factor
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
4.00
4.50
5.00
5.50
6.00+

W (Final)
(In

iti a
l

)

620

640

660

W

-100

-80

-60

-40

-20

0

20

40

60

80

100

Slide Analysis Information
SLIDE - An Interactive Slope Stability Program
Project Summary• File Name: Section Station 12 - RDD• Slide Modeler Version: 6.039• Project Title: SLIDE - An Interactive Slope Stability Program• Date Created: 3/29/2018, 4:22:35 PM

General Settings• Units of Measurement: Imperial Units• Time Units: days
• Permeability Units: feet/minute• Failure Direction: Right to Left
• Data Output: Standard• Maximum Material Properties: 20• Maximum Support Properties: 20

Analysis Options
Analysis Methods Used
• Spencer• Number of slices: 25• Tolerance: 0.005• Maximum number of iterations: 50• Check malpha < 0.2: Yes• Initial trial value of FS: 1• Steffensen Iteration: Yes

Groundwater Analysis• Groundwater Method: Water Surfaces• Pore Fluid Unit Weight: 62.4 lbs/ft3• Advanced Groundwater Method: Rapid Drawdown• Rapid Drawdown Method: Army Corp. Eng. 2 Stage (1970)

Random Numbers• Pseudo-random Seed: 10116• Random Number Generation Method: Park and Miller v.3

Surface Options• Search Method: Auto Refine Search• Divisions along slope: 15• Circles per division: 15• Number of iterations: 10• Divisions to use in next iteration: 50%• Number of vertices per surface: 12• Minimum Elevation: Not Defined• Minimum Depth: Not DefinedMaterial Properties
Property

Natural Soil

Existing Dam /Subgrade

Compacted
Earthfill

___

___

___

Color
Strength Type
Unit Weight [lbs/ft3]
Cohesion [psf]Friction Angle [deg]Water Surface
Hu Value
Rapid Drawdown
Undrained Behaviour
RD Shear Strength
Envelope Properties

MohrCoulomb
120
200
26
Water
Table
1

Method: spencer
X
Y
-41.8
674
-34.9006
674-33.6712
674-30.0991
674-27.949 674.216-25.7989 674.667-22.0997
675.9-18.5277 677.091-14.9556 678.721-11.6417 680.893-9.29162 682.809-6.68249
685.6

Valid / Invalid Surfaces

Toe Drain

___

___

MohrCoulomb
120
0
28
Water
Table
1

MohrCoulomb
120
0
32
Water
Table
1

120
100
17.5

Water Table

Water Table

1

1

Yes

Yes

Yes

CR: 400
PhiR: 10.8

CR: 150
PhiR: 10.8

CR: 100
PhiR: 10.8

FS: 1.210310
Axis Location: -35.841, 714.918
Left Slip Surface Endpoint: -41.800, 674.000
Right Slip Surface Endpoint: -6.682, 685.600
Resisting Moment=197719 lb-ft
Driving Moment=163363 lb-ft
Resisting Horizontal Force=4387.89 lb
Driving Horizontal Force=3625.44 lb
Total Slice Area=149.907 ft2

Topsoil

___

115
200
17.5

Method: spencer

Global Minimum Coordinates___

Lime Treated
Earthfill

MohrMohr-Coulomb
Coulomb
120
120
0
50
40
17.5
Water
Water Table
Table
1
1

Mohr-Coulomb Mohr-Coulomb

Global Minimums
•
•
•
•
•
•
•
•
•

Rock
Riprap

Method: spencer••

Number of Valid Surfaces: 12669
Number of Invalid Surfaces: 3082
Error Codes:
o Error Code -105 reported for 269 surfaceso Error Code -106 reported for 2265 surfaceso Error Code -108 reported for 500 surfaceso Error Code -111 reported for 1 surface
o Error Code -122 reported for 42 surfaceso Error Code -1000 reported for 5 surfaces
Error Codes
The following errors were encountered during the computation:o -105 = More than two surface / slope intersections with no valid slip surface.
o -106 = Average slice width is less than 0.0001 * (maximum horizontal extent of soil region). This limitation is
imposed to avoid numerical errors which may result from too many slices, or too small a slip region.
o -108 = Total driving moment or total driving force < 0.1. This is to limit the calculation of extremely high safety
factors if the driving force is very small (0.1 is an arbitrary number).
o -111 = safety factor equation did not convergeo -122 = Unable to compute undrained shear strength in drawdown stage. Most likely due to negative base effective
stresses.
o -1000 = No valid slip surfaces are generated at a grid center. Unable to draw a surface.

Slice Data
• Global Minimum Query (spencer) - Safety Factor: 1.21031
Slice
Width
Number[ft]

Weight[lbs]

1 1.60008 51.2025
2 1.60008 153.608
31.8496 305.167

41.8496 442.002

5 1.22946 369.514
6 1.78603 644.513
7 1.78603 772.115
8 1.07504 519.299
9 1.07504
10

551.6

2.1501 1169.78

11 1.23307 690.508
12 1.23307 690.509
13 1.23307

690.51

BaseMaterial
Topsoil
Topsoil
Lime Treated
Earthfill
Lime Treated
Earthfill
Lime Treated
Earthfill
Lime Treated
Earthfill
Lime Treated
Earthfill
Lime Treated
Earthfill
Lime Treated
Earthfill
Lime Treated
Earthfill
Lime Treated
Earthfill
Lime Treated
Earthfill
Lime Treated
Earthfill

0
0

Base
Shear
Shear
FrictionStress Strength
Angle
[psf]
[psf]
[degrees]
28 15.9875 19.3498
28 47.9625 58.0495

83.3854

0 68.8959 83.3854

183.9160183.916

0 77.8561

94.23

260.3570260.357

0 85.3153 103.258

323.990323.990 92.6209

112.1

386.310386.31122.572

0 101.273 122.572

460.1320460.132

123.5420 102.075 123.542

487.3990487.399127.662

0 105.479 127.662

517.2170517.217126.733

0 104.711 126.733

520.8290520.829146.619

0 121.142 146.619

506.5080506.508

156.7420 129.506 156.742

506.060506.06166.403

0 137.488 166.403

505.6320505.632

Base
Cohesion
[psf]

94.23
103.258
112.1

Base
Pore
NormalPressureStress[psf][psf]
36.39170109.1750Effective
NormalStress[psf]
36.3917109.175

14 1.19069 666.777
15 1.19069 666.776
16 1.19069 666.776
17 1.19068 656.302
18 1.19068 635.363
19 1.19068 614.425
20 1.65693 787.417
21 1.65693 681.342
22 1.17506 405.641
23 1.17506 325.763
24 1.30425 242.096
25 1.30489 89.7828

Lime Treated
Earthfill
Lime Treated
Earthfill
Lime Treated
Earthfill
Lime Treated
Earthfill
Lime Treated
Earthfill
Lime Treated
Earthfill
Lime Treated
Earthfill
Lime Treated
Earthfill
Lime Treated
Earthfill
Lime Treated
Earthfill
Lime Treated
Earthfill
Topsoil

175.637

0 145.117 175.637

505.220505.22181.527

0 149.984 181.527

504.9590504.959187.297

0 154.751 187.297

504.7020504.702187.607

0 155.007 187.607

464.7610464.761

187.36

0 154.803

187.36449.1680449.168

184.435

0 152.387 184.435

433.9330433.933

167.986

0 138.796 167.986

357.9590357.959151.564

0 125.227 151.564

308.0830308.083

128.974

0 106.563 128.974

234.9570234.957

112.432

0 92.8952 112.432

185.4580

185.458

85.1828070.381 85.1828

100.2210100.22128 18.3965 22.2655

41.8753041.87530Interslice Data
• Global Minimum Query (spencer) - Safety Factor: 1.21031
X
Y
Interslice
Interslice
Interslice
Slicecoordinate coordinate - Bottom Normal Force Shear Force Force Angle
Number
[ft]
[ft]
[lbs]
[lbs]
[degrees]
1
-41.8
674
0
0
0
2 -40.1999
674
25.5804
7.02752
15.3615
3 -38.5998
674
102.32228.1101
15.3614
4 -36.7502
674
229.747
63.1167
15.3615
5 -34.9006
674
373.742102.676
15.3616
6 -33.6712
674
478.637
131.49315.3615
7 -31.8851
674
644.071176.941
15.3615
8 -30.0991
674
824.96226.636
15.3615
9 -29.0241
674.108882.079
242.328
15.361510-27.949674.216939.638
258.1415.3615
11 -25.7989
674.667929.809255.4415.3615
12 -24.5659
675.078871.002239.284
15.3615
13 -23.3328
675.489822.693226.01315.3615
14 -22.0997
675.9
784.403215.49415.3615
15-20.909676.297756.671207.875
15.3615
16 -19.7183
676.694734.838201.877
15.3615
17 -18.5277
677.091718.782
197.466
15.361518-17.337677.634650.779178.784
15.3615
19 -16.1463
678.178591.008
162.36415.3615
20 -14.9556
678.721536.637
147.427
15.3615
21 -13.2987
679.807377.941103.82915.3615

22
23
24
25
26

-11.6417-10.4667-9.29162-7.98738-6.68249

List Of Coordinates
Water Table
X
Y
-100
679
-26.8006
679-26.7973 678.997-25.9374 678.221-25.5094
678.2-25.0573 678.164-23.4411 678.008-23.1506 677.992-21.6622 677.897-20.4438 677.817-19.7508 677.77-18.9137 677.687-17.2003 677.533-16.4986 677.283-15.7684 677.031-14.0734 676.357-12.7592 675.969-12.4015 675.858-11.1237 675.513-10.1387 675.217-9.56595 675.061-8.95385 674.895-7.87784 674.563-7.14957 674.378-5.93693 674.089-4.95801 673.853-4.21625 673.667-3.42137 673.468-2.49677 673.232-1.00234 672.88-0.585473 672.767-0.251348 672.676
1.35723 672.325
1.57304 672.282
2.7639 672.03
3.90601 671.802
4.40351671.7
5.9815 671.379
6.19501 671.336

680.893681.851682.809684.204685.6

250.919151.01
82.4686
34.4437068.9332
41.4859
22.6569.46249015.361515.361515.361515.36150

6.2583 671.322
7.83205 670.983
8.51357 670.848
9.25398 670.695
10.0752 670.524
10.9743 670.339
11.8063 670.161
12.8566 669.942
14.4952 669.578
14.5801 669.56
14.7331 669.528
16.1366 669.228
17.5821 668.924
17.856 668.867
17.9669 668.844
19.416 668.551
19.9638 668.44
20.0128 668.431
21.7824 668.064
22.5783 667.891
23.5745 667.684
25.2793 667.319
25.3942 667.295
25.4523 667.282
27.1966 666.91
28.0351 666.727
28.8432 666.554
30.469 666.181
30.6085 666.151
31.0766 666.042
32.3886 665.745
32.8174 665.632
34.0861 665.348
35.7629 664.973
35.8823 664.945
35.9618 664.927
37.856 664.512
38.6861 664.324
39.57 664.136
40.5053 663.951
41.5077 663.738
42.1369 663.611
43.486 663.351
44.0373 663.246
44.9215 663.079
46.3985 662.821
46.4023 662.821
48.1225 662.525
48.771 662.418

51.0166 662.077
51.2653 662.039
51.5806 661.995
52.8912 661.805
53.5862 661.713
54.2874 661.617
55.6241 661.452
56.2827 661.39
57.4727 661.243
58.8161 661.138
59.4365 661.063
61.0107 660.98
61.3853 660.962
61.4944 660.956
61.5963 660.95
63.7819 660.841
63.8249 660.838
64.4853660.8
65.8188 660.706
66.0774 660.675
67.9879 660.509
68.3663 660.437
68.8791 660.324
70.7995 660.114
71.7145 659.818
72.621 659.681
74.069 658.98
74.1053 658.972
74.1646 658.928
75.3593 658.222
75.6218657.2
76.276 656.767
77.0931 656.14
77.6361 655.605
77.7892 655.509
78.6
655
78.7852655
79.393655
80.8581
655
81.4
655
82.2073 655.055
82.655 655.088
83.0348 655.116
84.5851 655.195
85 655.221
85.2802 655.23
87.4151 655.336
88.2834 655.361
90.3063655.4

90.4154 655.402
90.514 655.403
92.6465 655.425
92.7426 655.425
94.9385 655.428
95.0286 655.428
97.1791 655.415
97.2674 655.415
97.3499 655.414
99.535 655.388
99.687 655.385
101.926 655.346
102.133 655.342
104.111 655.293
104.296 655.289
104.481 655.284
106.4 655.22
106.797 655.21
108.665 655.139
109.135 655.129
110.672655.1
111.091 655.091
111.545 655.085
112.906 655.058
113.468 655.049
113.956 655.041
114.955 655.039
114.995 655.039
115.908 655.031
116.4 655.03
116.692 655.027
117.084 655.024
117.294 655.022
117.607 655.02
117.652 655.019
117.707 655.019
118.024 655.016
118.203 655.015
118.68 655.011
118.949 655.009
119.455 655.006
120
655

Drawdown LineX
Y
-100 662.4
79.393 655
120 655

External BoundaryXY
120 640
120 656.3
108.8 656.3
95.4 660.8
81.4 660.8
7 685.6-7 685.6-26.8014 679-41.8 674
-48.2 674
-57.1261 671-60.1 670
-65.8 670
-82.8 664.3-89.9 663
-91.1 662.9-100 662.4-100 657.9-100 640.1

Material BoundaryXY-82.8 664.3-57.2 669
-53.8 670
-41.8 674
-38.6 674
-6.8 684.6
6.9 684.6
78.204 660.8
81.2 659.8
95.3 659.8
105.7 656.3
108.8 656.3

Material BoundaryXY-57.2 669
-42.8 669
-27.8 674
-5 681.6
5 681.6
61.5 660.8
70.4 657.2
78.6 657.2
81.4 657.2
85 657.2

100.6 657.2
105.7 656.3

Material BoundaryX
Y-60.1 670
-53.8 670

Material BoundaryX
Y-60.1 670
-60.1 669
-57.2 669

Material BoundaryX
Y-100 657.9-64.6 657.9
75.2 653
78.6 653
81.4 653
85 65385 657.2
90.4 655.5
111.2 655.5
113.7 656
120 656.3

Material BoundaryXY
61.5 660.8
78.204 660.8

Material BoundaryXY-38.6 674
-27.8 674

Material BoundaryXY
78.6 657.2
78.6 654.41
78.6
653
78.6
652
81.4
652
81.4
653
81.4 654.41
81.4 657.2