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Part 631 Geology
Rock Material Field
(210-VI-NEH, June 2002)
Washington. or call (202) 720-5964 (voice or TDD). Office of Civil Rights. religion. To file a complaint of discrimination.) Persons with disabilities who require alternate means for communication of program information (Braille. Director. (210-VI-NEH. large print. gender. age. sexual orientation. write USDA. June 2002) . audiotape. color. DC 20250-9410. (Not all prohibited bases apply to all programs. disability. Whitten Building.) should contact the USDA’s TARGET Center at (202) 720-2600 (voice and TDD). national origin. Room 326W. SW. and marital or family status. 14th and Independence Avenue. political beliefs.Chapter 12 Rock Material Field Classification System Part 631 National Enginnering Handbook Issued June 2002 The United States Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race. etc. USDA is an equal opportunity employer.
prepared chapter 12 of part 631 of the National Engineering Handbook. Moore. Natural Resources Conservation Service. national hydrogeologist. DC. Washington. (210-VI-NEH. June 2002) 12–i .Acknowledgment John S.
Chapter 12 12–ii Rock Material Field Classification System (210-VI-NEH. June 2002) Part 631 National Enginnering Handbook .
.......................1250 References Tables Table 12–1 Hydraulic erodibility in earth spillways 12–5 Table 12–2 Excavation characteristics 12–6 Table 12–3 Construction quality 12–7 Table 12–4 Fluid transmission 12–8 Table 12–5 Rock mass stability 12–9 Table 12–6 Correlation of various indicators of earth material excavatability Figures 12–12 Figure 12–1 Process for using the Rock Material Field Classification System (210-VI-NEH............................. 12–1 (b) History of RMFC system ...................................................................................................... 12–1 (e) Classification elements ................ 12–10 631........... 12–10 (b) Background ........................1210 The rock material field classification system 12–1 (a) Scope ................................................................... 12–1 (d) Outcrop confidence level ..............................1220 Evaluating earth material for excavation by a ripping index 12–10 (a) Purpose .... 12–1 (c) Rock unit .............................................. 12–2 (f) Classification process ............... 12–10 (c) Ripping index method .............................. 12–3 631........................................................................................................................................................ June 2002) 12–11 12–3 12–iii ....................................................................................................Chapter 12 Rock Material Field Classification System Contents: 631..............................................................................................
but not necessarily. tabular in form.1210 The rock material field classification system (a) Scope The NRCS uses the Rock Material Field Classification (RMFC) system to classify rock and assess rock performance for several engineering applications of rock. Its boundaries are (210–VI–NEH. Moore. retired). it can be defined by classification elements and analyzed for performance in relation to selected performance objectives. The second edition of TR-71. It is traced in the field by surface and subsurface mapping techniques. and hydraulic properties. mass movement. The three levels of outcrop confidence are defined as: (b) History of RMFC system The RMFC system was first issued in 1984 as SCS Technical Release 71. uniformity in thickness is not a determining factor. or buried topography. The system is designed for use by personnel trained in its use and knowledgeable of its limitations. 1988). hydraulic erodibility in earth spillways and excavation characteristics were updated to reflect recent findings from field and laboratory research. (d) Outcrop confidence level Outcrop confidence is the relative measure of the predictability or homogeneity of the structural domain and the lithology of the rock unit from one exposure to another or to the proposed site of investigation. Classification (by any system) alone does not preclude or replace laboratory testing for specific engineering design purposes. (c) Rock unit Level 1: High—Rock units are massive and homogeneous. Peter V. Significant and frequent lateral and vertical changes can be expected. A rock unit is consistent in its mineralogical composition. Structural features produced by tectonic activity tend to be systematic in orientation and spacing. but differs in that the body need not have been formed under uniform physicochemical conditions. rock units need not conform to formally recognized stratigraphic rock formations. delineated by measurable or otherwise describable physical properties or features.Chapter 12 Rock Material Field Classification System 631. Because the mapping criteria are performance based engineering characteristics.52. and are vertically and laterally extensive. June 2002) 12–1 . The edition presented here was prepared under the guidance of John S. It is defined as a body of rock that is identified in the field and mapped according to measurable or otherwise describable physical properties or features at a scale useful for project analysis. Level II: Intermediate—Rock characteristics are generally predictable. A critique of this edition was published in ASTM STP-984 (Moore. Classification criteria for two engineering performance objectives. NRCS geologist. had revisions made by John S. but have expected lateral and vertical variability. The rock unit is the basic mapping unit for the RMFC system. Paterson (SCS. Moore. Forest Service. It was prepared by Louis Kirkaldie (SCS. Other performance objectives were updated to conform to the field procedures for describing various rock parameters presented in NEH 628. issued in 1987. Williamson (USDA. Once a rock unit has been established. Site geology has a history of low tectonic activity. The term rock unit is similar to lithosome in that the body of rock has consistent. retired). The body is prevailingly. mappable characteristics. and Douglas A. It is particularly suited to describing rock material in support of NRCS engineering activities at the reconnaissance and preliminary (planning) levels. geologic structure. retired). Level III: Low—Rock conditions are extremely variable because of complex depositional or structural history.
and geohydrologic properties.52. They include many 12–2 Part 631 National Engineering Handbook Rock Material Field Classification System types of discontinuities. rock mass properties are too large or extensive to be observed directly in their entirety at a single outcrop and are difficult or impossible to sample for laboratory analysis. dominate the strength of a rock mass where discontinuities are widely spaced or nonexistent.Chapter 12 (e) Classification elements Classification elements are objective physical properties of a rock unit that define its engineering characteristics. table 10) • Large geomorphic features (karst topography. table 14) • Joint count number (use NEH 628. outcroppings. discontinuities inevitably lower the strength and stability of a rock mass and reduce (210–VI–NEH. the structural characteristics of the in situ rock mass. appendix 52C. lava flows. and disturbed samples using qualitative procedures and simple classification tests. table 13) • Aperture category (use NEH 628. appendix 52C. Standard Test Method for Determining Rock Quality Designation (RQD) of Rock Core) • Other geophysical survey parameters (ground penetrating radar. table 11) • Joint persistence category (use NEH 628. The mechanical behavior and strength of a rock mass are commonly dominated more by mass properties than by material properties. June 2002) . a rock mass composed of the strongest intact rock material is weakened in proportion to the number of discontinuities in a given volume. faults. or the effects of its mode of emplacement. appendix 52C. core sections. appendix 52C. resistivity. table 5) • Unit weight (dry) (use NEH 628. vugs. They do not account for the influence of discontinuities or boundary conditions of the rock. rock mass properties. joints. unconformities) • Types of major voids (caverns. Engineering classification of a rock unit takes into consideration the material properties of the rock itself. electromagnetic. table 3) • Color (use NEH 628. note type of cement and presence of alterable minerals) • Primary porosity (free draining or not) • Discrete rock particle size (use D50 or cube root of the product of its three dimensions) • Hardness category (use NEH 628. such as fractures. deposition. Guide for Selection of Surface Geophysical Methods) The properties of a rock mass are often significantly different from the properties of intact rock samples of the same rock mass. or in the laboratory using standard test methods. For example. lava tubes) • Seismic velocity (seismic refraction survey. The results are applicable to hand specimens and representative samples of intact rock material. and the flow of water contained in the rock or within the system of discontinuities. exfoliation) • Large geologic structures (folds. appendix 52C. sinkholes. Normally. characteristics. table 1) (2) Rock mass properties Rock mass properties are measurable or otherwise describable lithologic properties. table 52-6) • Roughness condition of joint walls (use NEH 628. Typical classification elements include: • Principal rock type (see NEH 628. appendix 52C. appendix 52C. use ASTM D 6429. on the other hand. or features of the rock mass that must be evaluated on a macroscopic scale in the field. table 4) • Mineralogy (estimate percentage of principal and accessory minerals. appendix 52C. table 5) • Unconfined compressive strength (use NEH 628. drill cuttings. as well as abrupt changes in lithology because of erosion. Typical classification elements include: • Discontinuity type (use NEH 628. The properties are determined from examination of hand specimens. table 12) • Joint set spacing category (use NEH 628. and faults. appendix 52C. Standard Guide for Using the Seismic Refraction Method for Subsurface Investigation) • RQD (use ASTM D 6032. (1) Rock material properties Rock material properties are measurable or otherwise describable lithologic properties of intact rock material that can be evaluated in hand specimen and thus can be subjected to meaningful inquiry in the laboratory. appendix 52C. The RMFC system uses three major types of classification elements: rock material properties. appendix 52C. Rock material properties are related to the physical properties of the constituent minerals and the type of mineral bonding. lineaments. gravity. use ASTM D 5777. table 9) • Type of joint infilling (gouge) (use NEH 628. Thus. Material properties.
The outcrop confidence level should be determined and recorded in the notes. such as primary porosity and permeability. Laboratory tests are used to evaluate geohydrologic properties of the rock material.Chapter 12 Part 631 National Engineering Handbook Rock Material Field Classification System the amount of energy required to excavate. and conducting the performance assessment. leaky artesian. perched) • Electrical conductivity (geophysical survey) (1) Identify rock units Rock unit identification includes determining the location and extent of each mappable unit in outcrop or in stratigraphic section at and near the site. such as Rock Unit L-6. it may be considered a rock unit (as defined in this chapter) and identified by its formal stratigraphic name. or otherwise destabilize the rock mass. When done in conjunction with a review of available data. Geohydrologic properties include material and mass properties. blast. and literature. describing them in terms of appropriate classification elements. (3) Geohydrologic properties Geohydrologic properties are attributes of a rock unit that affect the mode of occurrence. depth. Field tests are typically used to evaluate geohydrologic properties of the rock mass. this fieldwork should provide the outcrop confidence level. hydraulic conductivity. The performance assessment includes selecting the performance objectives for the proposed engineering uses of the rock and classifying the rock material within each selected objective. but also account for the interaction and behavior of subsurface water within the rock mass. date of measurement) • Aquifer type (unconfined. such as Vishnu schist. published information) • Soluble rock (occurrence of limestone. All other mappable rock units should be assigned alphanumeric designations. maps. Typical classification elements include: • Primary porosity (use data collected for rock material properties) • Secondary porosity (use data collected for rock mass properties) • Hydraulic conductivity (pump tests. Figure 12–1 schematically illustrates the basic steps in the process. and elevation. Each unit should be located on a geologic map by stationing. distribution. gypsum. published information) • Transmissivity (pump tests. transmissivity. or dolomite. confined. erode. including secondary porosity. see data collected for rock material properties) • Water table/potentiometric surface (measured in field. remove. published data. published information) • Storativity/specific yield (pump tests. (210–VI–NEH. Figure 12–1 Process for using the Rock Material Field Classification system 1 Identification rock units 2 Description of rock units by classification elements • Rock material • Rock mass properties • Geohydrologic properties 3 Selection of performance objectives • Hydraulic erodibility in earth spillways • Excavation characteristics • Construction quality • Fluid transmission • Rock mass stability 4 Classification by objective • Determine class of rock or each selected performance objective (f) Classification process The classification process consists of identifying the rock units at the site of investigation. June 2002) 12–3 . and flow characteristics of subsurface water within the unit. location. If a formally recognized geologic formation is expected to perform as a homogeneous mass for engineering purposes. and other hydraulic parameters.
springs. use table 12–3. remote imagery interpretation. Therefore. use table 12–1. For hydraulic erodibility in earth spillways. and for salt water intrusion. End member classes I and III for each performance objective are intentionally defined restrictively. core sections. and piezometers. and disturbed samples using conventional geologic terminology. For rock mass stability. fixed line survey. Tables 12–1 through 12–5 provide the criteria for applicable classification elements that define each class for the five performance objectives considered in this system. and geomorphic analysis. review of logs/data from water wells. use table 12–5. drill holes. canals.Chapter 12 Part 631 National Engineering Handbook Rock Material Field Classification System (2) Describe rock units by classification elements Each rock unit is characterized in terms of specific classification elements that affect performance of the rock for its intended use. which covers analysis of rock quality for riprap. core sample analysis. Rock units assigned to the same class within a given performance objective can be expected to perform similarly. which covers evaluation of erodibility of rock subject to intermittent flowing water. aggregate. embankment fill. for engineering subdrainage for slope stability and for point and nonpoint 12–4 (210–VI–NEH. Each of the five performance objectives has three classes of rock material (tables 12–1 through 12–5). rock material that classifies as class II is usually an indication that additional evaluation may be needed than just what is considered in the tables. and dam foundations. Geohydrologic properties—Determined by pressure testing. (4) Classification by objective Determining the class of the rock material for all identified performance objectives is the final step in the procedure. aquifers. review of published and unpublished maps and reports. and road armor for construction applications. June 2002) . The investigator may include any additional elements considered necessary for further clarification and refinement. interpretation of rock material and rock mass properties. drill cuttings. use table 12–4. For water transmission. and dye tests. For excavation characteristics. for excavation dewatering. geophysical survey. Rock material properties—Determined by examining and classifying hand specimens. observation wells. basins) for ground water recharge or disposal. outcroppings. A class defines the expected capabilities and limitations of the rock for each engineering use. for ground water yield for water supply development (water wells. which covers evaluation of the potential for water transmission through primary and secondary porosity in rock units underlying reservoirs. use table 12–2. Rock mass properties—Determined by geologic mapping. which covers evaluation of rock mass stability of natural or constructed slopes for gravity or seismic activity. which covers evaluation of excavation characteristics of rock. source pollution. For construction quality. (3) Select performance objectives This step involves the selection of performance objectives (engineering uses) of the rock for which an assessment of engineering performance is needed.
0 m/hr (10 ft/hr) at a unit discharge of 9.0 m/hr (1 to 10 ft/hr) at a unit discharge of 9.2 m3/s/m (100 ft3/s/ft) and 9 m (30 ft) of energy head.3 m/hr (1 ft/hr) at a unit discharge of 9.2 m3/s/m (100 ft3/s/ft) and 9 m (30 ft) of energy head. June 2002) Rock material experiences headcut erosion rates greater than 3. which comprises: Material strength Block size Discontinuity shear strength Relative ground structure kh ≥ 100 Rock material experiences headcut erosion rates from 0. kh (NEH 628.2 m3/s/m (100 ft3/s/ft) and 9 m (30 ft) of energy head.52). Must fulfill the following condition: 1 ≤ kh ≤ 10 12–5 . Must fulfill the following condition: Headcut erodibility index.Chapter 12 Table 12–1 Part 631 National Engineering Handbook Rock Material Field Classification System Hydraulic erodibility in earth spillways Classification elements Class I Class II Class III Highly erosion resistant Erosion resistant Moderately erosion resistant Rock material experiences headcut erosion rates less than 0. Must fulfill the following condition: 10 < kh < 100 (210–VI–NEH.3 to 3.
000 ft/s) Minimum equipment size (flywheel power) required to excavate rock. 21). 21).000 185 kW (250 hp) 110 kW (150 hp) 1/ The classification in no way implies the actual contract payment method to be used or supersedes NRCS contract documents. kh (NEH 628. 260 kW (350 hp). 1997) ≥ 2.450 m/s (≥ 8.000 ft/s) ≤ 2. All machines assumed to be heavy-duty. approximate (ASTM D 5777 and Caterpillar Handbook of Ripping. Must fulfill all conditions below: Rock material requires ripping techniques for excavation may classify 1 as rock excavation (NRCS Construction Spec.150–2.000 375 kW (500 hp). track-type backhoes or tractors equipped with a single tine. The classification is for engineering design purposes only. 21).000 Blasting.450 m/s (7. Must fulfill all conditions below: Rock material can be excavated as common material by earthmoving or ripping equipment may classify 1 as common excavation (NRCS Construction Spec.150 m/s (≤ 7. Must fulfill the all conditions below: Headcut erodibility index.52) kh ≥ 100 10 < kh < 100 kh ≤ 10 Seismic velocity.000–8. for kh ≤ 10. rear-mounted ripper. 12–6 (210–VI–NEH.000 ft/s) 2.Chapter 12 Table 12–2 Part 631 National Engineering Handbook Rock Material Field Classification System Excavation characteristics Classification elements Class I Class II Very hard ripping to blasting Hard ripping Class III Easy ripping Rock material requires drilling and explosives or impact procedures for excavation may classify 1 as rock excavation (NRCS Construction Spec. for kh > 10. for kh < 1. June 2002) .
table 3) > 2.52. filter. table 52–4) Hard to extremely hard rock Moderately hard rock Moderately soft to very soft rock Unit weight (NEH 628.52.5 MPa (< 1.800 lb/in2) Hardness (NEH 628. May require additional evaluation if at least one condition below is fulfilled: Rock material is unsuitable for aggregate.Chapter 12 Table 12–3 Part 631 National Engineering Handbook Rock Material Field Classification System Construction quality Classification elements Class I Class II Class III High grade Medium grade Low grade Rock material is suitable for high stress aggregate.5–50 MPa (1. and other construction applications requiring high durability.250 lb/in2) < 12.08–2.52. or riprap. appendix 52C. Must fulfill at least one condition below: Strength (NEH 628. riprap. and drain material.24 g/cm3 (> 140 lb/ft3) 2. June 2002) 12–7 .24 g/cm3 (130–140 lb/ft3) < 2. filter and drain material. Must fulfill all conditions below: Rock material is potentially suitable for construction applications.250 lb/in2) 12. Reacts essentially as a soil material in embankments.08 g/cm3 (< 130 lb/ft3) (210–VI–NEH. table 52–4) > 50 MPa (> 7.800–7.
May require additional evaluation if at least one condition below is fulfilled. such as lime stone.3 ft/d) > 10-5 m/s (> 3 ft/d) Transmissivity (irrigation wells) < 10-3 m2/s (< 103 ft2/d) > 1 m2/s (> 105 ft2/d) Transmissivity (domestic/ stock wells) < 10-6 m2/s (< 1 ft2/d) > 10-4 m2/s (> 102 ft2/d) 12–8 (210–VI–NEH. enlarged joints). solutional (caverns. stress relief joints) No major voids occur in rock mass Any types of major voids occur in rock mass Hydraulic conductivity (dams) < 10-6 m/s (< 0. Primary porosity Very low primary porosity. marble. Soluble rock.52. Must fulfill at least one condition below. depositional (lava tubes or interbedded gravels and lava beds) or structural/tectonic (faults. nonswelling fines matrix Joints open or filled with sand or gravel with < 15% cohesionless. hairline (<2 mm) Very narrow to narrow (2–6 mm) Narrow to wide (≥ 6 mm) Infilling (gouge) Joints tight or filled with cohesive. is the predominant rock type. if present. June 2002) Pores visible to naked eye. plastic clay or swelling fines matrix Joints open or filled with nonplastic. gypsum. Pores visible under l0x pores not interconnected hand lens. table 14) Extremely narrow. Rock material has potential to transmit water.Chapter 12 Table 12-4 Part 631 National Engineering Handbook Rock Material Field Classification System Fluid transmission Classification elements Class I Class II Class III Slowly permeable Moderately permeable Highly permeable Rock material has low capability to transmit water. Rock material has high capability to transmit water. sinkholes. dolomite. or rock mass intact and massive ≤ 2 joint sets and random fractures ≥ 3 interconnecting joint sets Joint aperture category (NEH 628. slowly free or free draining draining Number of joint sets (include bedding plane partings) 1 joint set and random fractures. appendix 52C. generally through primary porosity. occurs as a minor or secondary constituent in the rock mass Soluble rock. Must fulfill all conditions below. generally through secondary porosity. nonplastic fines matrix Major voids. Soluble rock No soluble rock occurs in the rock mass. rapidly free draining . or halite.
5–50 MPa (1.5 MPa (< 1.800–7. or rock mass intact and massive. table 52–4) Hard to extremely hard rock Moderately hard rock Moderately soft to very soft rock RQD (ASTM D 6032) > 75 25–75 < 25 Number of joint sets in rock mass (include bedding plane partings) 1 joint set and random fractures.Chapter 12 Table 12–5 Part 631 National Engineering Handbook Rock Material Field Classification System Rock mass stability Classification elements Class I Class II Class III Stable Potentially unstable Unstable Rock material has very low potential for instability. table 52–4) > 50 MPa (> 7. Must fulfill all conditions below: Rock material has potential for instability. no adverse component of dip ≤ 2 joint sets plus random fractures. Must fulfill at least one condition below: Strength (NEH 628.52.250 lb/in2) 12. June 2002) 12–9 . May require additional evaluation if at least one condition below is fulfilled: Rock material has significant potential for instability. no set contains adverse component of dip ≥ 3 interconnecting joint sets.250 lb/in2) < 12. and ≥ 1 set contains adverse component of dip Joint water condition Unconfined Unconfined Confined (210–VI–NEH.800 lb/in2) Hardness (NEH 628.52.
Table 12–6 correlates various parameters that indicate the excavatability of the full spectrum of earth material. 1997) is part of the Earth Spillway Erosion Model described in NEH 628. The ripping index is determined by following the same procedures used in determining the headcut erodibility index (NEH 628. and Kirsten (1994) developed the concept of a headcut erodibility index based on the analogy between bulldozer drawbar power required for ripping earth material and the hydraulic power associated with turbulent energy dissipation at a headcut.51. One of the criteria defining rock excavation is the need to use either heavy ripping equipment (rated above 250 flywheel horsepower) or blasting to achieve excavation. In the first column. The final column indicates the class of rock for excavation characteristics (table 12–2) in the RMFC system. The classification system for the headcut erodibility index. The excavation class (rock or common). The index allows estimation of the minimum energy or effort required for excavation. Both indexes comprise the same rock material and rock mass parameters.52). 12–10 (210–VI–NEH. provides criteria for defining rock excavation and common excavation.1220 Evaluating earth material for excavation by a ripping index Excavation characteristics of any given earth material are readily established by calculating the material's ripping index. Moore. This section describes the ripping index method for predicting the excavatability of any earth material. Excavation. on a scale ranging from hand tools to drilling and blasting. (a) Purpose NRCS Construction Specification 21. Kirsten’s ripping index. kh (Temple and Moore. The second column provides the minimum tools required for excavation. kn. June 2002) .Chapter 12 Part 631 National Engineering Handbook Rock Material Field Classification System (c) Ripping Index method 631. for pay purposes. (b) Background An earth material classification system developed by Kirsten (1982 and 1988) was field proven by ripping trials to reasonably accurately predict the excavation characteristics of a broad range of earth material. is provided in parentheses. Determining the ripping index or seismic velocity allows prediction of the minimum size machine needed (expressed in flywheel horsepower) to excavate the material. as defined in NRCS Construction Specification 21. Temple. earth material is delineated by hardness. allows earth material to be classified on a continuous basis from soft soil through hard rock. Excavation.
000 — I Because ripping index. track-type backhoe or tractor equipped with a single tooth.000 ≥ 250 II 100–1.000–8. table 52–4) Very hard ripping (rock 5) Extremely hard rock (NEH 628. (210–VI–NEH.000 –10. use kh. Excavation. tables 52–2 & 52–3) Hand tools (common 4) < 0.52.52.000 ≥ 100 — 1. tables 52–2 & 52–3) Power tools (common 4) 0.000 8. Flywheel horsepower. rear-mounted ripper. table 52–4) Hard ripping (rock 5) Very hard rock (NEH 628. The classification is for engineering design purposes only.0 Soft through moderately soft rock (NEH 628. 1988 and 1988) is equal to headcut erodibility index. table 52–4) Extremely hard ripping to blasting (rock 5) Drilling and blasting (rock 5) 1/ 2/ 3/ 4/ 5/ Equipment 3 needed for excavation (hp) RMFC system class (table 12–2) — — 2.52. Meets criteria for rock excavation in NRCS Construction Specification 21. Meets criteria for common excavation in NRCS Construction Specification 21. Excavation.000–5.000 9. kh (NEH 628.000 ≥ 350 I 1. (Kirsten. Seismic velocity values are approximate. table 52–4) Easy ripping (common 4) Moderately hard through hard rock (NEH 628.10–1.000–10.000 ≥ 500 I > 10.52. Note: The classification in no way implies the actual contract payment method to be used or supersedes NRCS contract documents.000 > 10. taken from ASTM D 5777 and Caterpillar Handbook of Ripping (1997).000 Stiff cohesive soil or dense cohesionless soil through very soft rock or hard. machines assumed to be heavy-duty.52.52). rock-like material (NEH 628.10 < 2. kn.0–10 5.000–7.000 ≥ 150 III 10–100 7. June 2002) 12–11 .Chapter 12 Table 12–6 Part 631 National Engineering Handbook Rock Material Field Classification System Correlation of various indicators of earth material excavatability Earth material hardness Ripping index 1 (kn) Excavation description excavation class Seismic velocity 2 (ft/s) Very soft through firm cohesive soil or very loose through medium dense cohesionless soil (NEH 628.52.000–9.
June 2002) .. Annual book of ASTM standards: Section 4. Temple.Chapter 12 Part 631 National Engineering Handbook Rock Material Field Classification System 631. American Society for Testing and Materials. pp. In Rock Classification Systems for Engineering Purposes. (standards D 2487. IL.). 3.). L. N. ASTM STP-984. L.D. West Conshohocken. 1988. and J. Transactions of the American Society of Agricultural Engineers. Moore.). American Society for Testing and Materials. 292–308 (discussion in vol. In Rock Classification Systems for Engineering Purposes: L. D. Critique of the rock material field classification procedure. 1997. Barton. H. 2.S. 1988. Construction. pp. ASTM. West Conshohocken. 40. N. May 1983). Inc. 1997. Kirsten. 11 ed. Moore. 19428. Case histories of groundmass characterization for excavatability. 1988. 5. Lunde. 31. West Conshohocken. Kirsten. 19428. Temple. No. H.D. In Rock Classification Systems for Engineering Purposes. 1994. 102–120.D. Rock Mechanics. 189– 236. A classification system for excavation in natural materials. pp. PA 19428.. Moore. (ed. pp. D. 30 pp.A.M. Vol. PA 19428. J.M. Kirkaldie (ed.S.A. Rock mass classification and tunnel reinforcement selection using the Q-System. 12–12 (210–VI–NEH. D 6429). West Conshohocken. 557–562. American Society for Testing and Materials. Headcut advance threshold in earth spillways. 25. Kirkaldie. D 2488. Barton. 159–184.S. pp. R. Handbook of ripping. pp. 52–58. Kirsten. The Civil Engineer in South Africa. PA. Bulletin of the Association of Engineering Geologists. Peoria.. 1974.A.09. Vol. Headcut advance prediction for earth spillways. 6. PA. ASTM STP-984. Kirkaldie (ed. 04.1250 References American Society for Testing and Materials.08 and 04. Vol. and H. pp. J. No. AEDK0752–01. Lien. Engineering classification of rock masses for the design of tunnel support. Caterpillar. D 6032. STP-984. 277–280. Vol. no. 1982. D 5777. and J.
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