1、Designation: D2487 11D2487 17Standard Practice forClassification of Soils for Engineering Purposes (UnifiedSoil Classification System)1This standard is issued under the fixed designation D2487; the number immediately following the designation indicates the year oforiginal adoption or, in the case of
2、 revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S. Department of Defense.1. Scope*1.1 This pra
3、ctice describes a system for classifying mineral and organo-mineral soils for engineering purposes based onlaboratory determination of particle-size characteristics, liquid limit, and plasticity index and shall be used when preciseclassification is required.NOTE 1Use of this standard will result in
4、a single classification group symbol and group name except when a soil contains 5 to 12 % fines or whenthe plot of the liquid limit and plasticity index values falls into the crosshatched area of the plasticity chart. In these two cases, a dual symbol is used,for example, GP-GM, CL-ML. When the labo
5、ratory test results indicate that the soil is close to another soil classification group, the borderline conditioncan be indicated with two symbols separated by a slash. The first symbol should be the one based on this standard, for example, CL/CH, GM/SM, SC/CL.Borderline symbols are particularly us
6、eful when the liquid limit value of clayey soils is close to 50. These soils can have expansive characteristics andthe use of a borderline symbol (CL/CH, CH/CL) will alert the user of the assigned classifications of expansive potential.1.2 The group symbol portion of this system is based on laborato
7、ry tests performed on the portion of a soil sample passing the3-in. (75-mm) sieve (see Specification E11).1.3 As a classification system, this standard is limited to naturally occurring soils.NOTE 2The group names and symbols used in this test method may be used as a descriptive system applied to su
8、ch materials as shale, claystone,shells, crushed rock, etc. See Appendix X2.1.4 This standard is for qualitative application only.NOTE 3When quantitative information is required for detailed designs of important structures, this test method must be supplemented by laboratorytests or other quantitati
9、ve data to determine performance characteristics under expected field conditions.1.5 This standard is the ASTM version of the Unified Soil Classification System. The basis for the classification scheme is theAirfield Classification System developed byA. Casagrande in the early 1940s.2 It became know
10、n as the Unified Soil ClassificationSystem when several U.S. Government Agencies adopted a modified version of the Airfield System in 1952.1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard t
11、o establish appropriate safety safety, health, and healthenvironmental practices and determine theapplicability of regulatory limitations prior to use.1.7 This practice offers a set of instructions for performing one or more specific operations. This document cannot replaceeducation or experience an
12、d should be used in conjunction with professional judgment. Not all aspects of this practice may beapplicable in all circumstances. This ASTM standard is not intended to represent or replace the standard of care by which theadequacy of a given professional service must be judged, nor should this doc
13、ument be applied without consideration of a projectsmany unique aspects. The word “Standard” in the title of this document means only that the document has been approved throughthe ASTM consensus process.1.8 This international standard was developed in accordance with internationally recognized prin
14、ciples on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.1 This practice is under the jurisdiction of ASTM Committee D18 on Soil and
15、Rock and is the direct responsibility of Subcommittee D18.07 on Identification andClassification of Soils.Current edition approved May 1, 2011Dec. 15, 2017. Published June 2011January 2018. Originally approved in 1966. Last previous edition approved in 20102011 asD2487 10.11. DOI: 10.1520/D2487-11.
16、10.1520/D2487-17.2 Casagrande, A., “Classification and Identification of Soils,” Transactions, ASCE, 1948 , p. 901.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may no
17、t be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the en
18、d of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States12. Referenced Documents2.1 ASTM Standards:3C117 Test Method for Materials Finer than 75-m (No. 200) Sieve in Mineral Aggregates by WashingC136 Test Method for Sieve Ana
19、lysis of Fine and Coarse AggregatesC702 Practice for Reducing Samples of Aggregate to Testing SizeD420 Guide to Site Characterization for Engineering Design and Construction Purposes (Withdrawn 2011)4D422 Test Method for Particle-Size Analysis of Soils (Withdrawn 2016)4D653 Terminology Relating to S
20、oil, Rock, and Contained FluidsD1140 Test Methods for Determining the Amount of Material Finer than 75-m (No. 200) Sieve in Soils by WashingD2216 Test Methods for Laboratory Determination of Water (Moisture) Content of Soil and Rock by MassD2488 Practice for Description and Identification of Soils (
21、Visual-Manual Procedures)D3740 Practice for Minimum Requirements for Agencies Engaged in Testing and/or Inspection of Soil and Rock as Used inEngineering Design and ConstructionD4083 Practice for Description of Frozen Soils (Visual-Manual Procedure)D4318 Test Methods for Liquid Limit, Plastic Limit,
22、 and Plasticity Index of SoilsD4427 Classification of Peat Samples by Laboratory TestingD6913 Test Methods for Particle-Size Distribution (Gradation) of Soils Using Sieve AnalysisE11 Specification for Woven Wire Test Sieve Cloth and Test Sieves3. Terminology3.1 Definitions:3.1.1 Except as listed bel
23、ow, all definitions are in accordance with Terminology D653.NOTE 4For particles retained on a 3-in. (75-mm) U.S. standard sieve, the following definitions are suggested:Cobblesparticles of rock that will pass a 12-in. (300-mm) square opening and be retained on a 3-in. (75-mm) U.S. standard sieve, an
24、dBouldersparticles of rock that will not pass a 12-in. (300-mm) square opening.3.1.2 claysoil passing a No. 200 (75-m) U.S. standard sieve that can be made to exhibit plasticity (putty-like properties)within a range of water contents and that exhibits considerable strength when air dry. For classifi
25、cation, a clay is a fine-grainedsoil, or the fine-grained portion of a soil, with a plasticity index equal to or greater than 4, and the plot of plasticity index versusliquid limit falls on or above the “A” line.3.1.3 gravelparticles of rock that will pass a 3-in. (75-mm) sieve and be retained on a
26、No. 4 (4.75-mm) U.S. standard sievewith the following subdivisions:Coarsepasses 3-in. (75-mm) sieve and retained on 34-in. (19-mm) sieve, andFinepasses 34-in. (19-mm) sieve and retained on No. 4 (4.75-mm) sieve.3.1.4 organic claya clay with sufficient organic content to influence the soil properties
27、. For classification, an organic clay isa soil that would be classified as a clay except that its liquid limit value after oven drying is less than 75 % of its liquid limit valuebefore oven drying.3.1.5 organic silta silt with sufficient organic content to influence the soil properties. For classifi
28、cation, an organic silt is a soilthat would be classified as a silt except that its liquid limit value after oven drying is less than 75 % of its liquid limit value beforeoven drying.3.1.6 peata soil composed of vegetable tissue in various stages of decomposition usually with an organic odor, a dark
29、-brownto black color, a spongy consistency, and a texture ranging from fibrous to amorphous.3.1.7 sandparticles of rock that will pass a No. 4 (4.75-mm) sieve and be retained on a No. 200 (75-m) U.S. standard sievewith the following subdivisions:Coarsepasses No. 4 (4.75-mm) sieve and retained on No.
30、 10 (2.00-mm) sieve,Mediumpasses No. 10 (2.00-mm) sieve and retained on No. 40 (425-m) sieve, andFinepasses No. 40 (425-m) sieve and retained on No. 200 (75-m) sieve.3.1.8 siltsoil passing a No. 200 (75-m) U.S. standard sieve that is nonplastic or very slightly plastic and that exhibits littleor no
31、strength when air dry. For classification, a silt is a fine-grained soil, or the fine-grained portion of a soil, with a plasticityindex less than 4 or if the plot of plasticity index versus liquid limit falls below the “A” line.3.2 Definitions of Terms Specific to This Standard:3.2.1 coeffcient of c
32、urvature, Ccthe ratio (D30)2/(D10 D60), where D60, D30, and D10 are the particle sizes corresponding to60, 30, and 10 % finer on the cumulative particle-size distribution curve, respectively.3.2.2 coeffcient of uniformity, Cuthe ratio D60/D10, where D60 and D10 are the particle diameters correspondi
33、ng to 60 and10 % finer on the cumulative particle-size distribution curve, respectively.3 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summar
34、y page on the ASTM website.D2487 1724. Summary4.1 As illustrated in Table 1, this classification system identifies three major soil divisions: coarse-grained soils, fine-grainedsoils, and highly organic soils. These three divisions are further subdivided into a total of 15 basic soil groups.4.2 Base
35、d on the results of visual observations and prescribed laboratory tests, a soil is catalogued according to the basic soilgroups, assigned a group symbol(s) and name, and thereby classified. The flow charts, Fig.Figs. 1 and 2 1for fine-grained soils,and Fig. 3 for coarse-grained soils, can be used to
36、 assign the appropriate group symbol(s) and name.TABLE 1 Soil Classification ChartSoil ClassificationCriteria for Assigning Group Symbols and Group Names Using Laboratory TestsA GroupSymbol Group NameBCOARSE-GRAINEDSOILSGravels(More than 50 %of coarse fraction retainedonNo. 4 sieve)Clean Gravels(Les
37、s than 5 % finesC )Cu $ 4 and 1 # Cc # 3D GW Well-graded gravelECOARSE-GRAINEDSOILSGravels(More than 50 %of coarse fraction retainedonNo. 4 sieve)Clean Gravels(Less than 5 % finesC )Cu $ 4.0 and1 # Cc # 3.0DGWMore than 50 %retained on No. 200 sieveCu 3DGP Poorly graded gravelEMore than 50 %retained
38、on No. 200 sieveCu 3.0DGP Poorly graded gravelEGravels with Fines(More than 12 % finesC )Fines classify as ML or MH GM Silty gravelE,F,GFines classify as CL or CH GC Clayey gravelESands(50 % or more of coarsefraction passesNo. 4 sieve)Clean Sands(Less than 5 % finesH )Cu $ 6 and 1 # Cc # 3D SW Well-
39、graded sandSands(50 % or more of coarsefraction passesNo. 4 sieve)Clean Sands(Less than 5 % finesH )Cu $ 6.0 and 1.0Cu 3DSPCu 3.0DSP Poorly graded sandISands with Fines(More than 12 % finesH )Fines classify as ML orMHSM Silty sandF,G,IFines classify as CL orCHSC Clayey sandF,G,IFINE-GRAINED SOILS Si
40、lts and Clays inorganic PI 7 and plots on orabove “A” lineJCL Lean clayK,L,M50 % or morepasses the No. 200 sieveLiquid limitless than 50PI 4 or plots below “A”lineJML SiltK ,L,Morganic Liquid limit oven driedLiquid limit not dried 0.75 OL Organic clayK,L,M,NOrganic siltK,L,M,OSilts and Clays inorgan
41、ic PI plots on or above “A”lineCH Fat clayK ,L,MLiquid limit50 or morePI plots below “A” line MH Elastic siltK,L,Morganic Liquid limit oven driedLiquid limit not dried 0.75 OH Organic clayK,L,M,POrganic siltK,L,M,QHIGHLY ORGANIC SOILS Primarily organic matter, dark in color, and organic odor PT Peat
42、A Based on the material passing the 3-in. (75-mm) sieve.B If field sample contained cobbles or boulders, or both, add “with cobbles or boulders, or both” to group name.C Gravels with 5 to 12 % fines require dual symbols:GW-GM well-graded gravel with siltGW-GC well-graded gravel with clayGP-GM poorly
43、 graded gravel with siltGP-GC poorly graded gravel with clayD Cu5D60/D10 Cc5sD 30d2D103D 60E If soil contains $15 % sand, add “with sand” to group name.F If fines classify as CL-ML, use dual symbol GC-GM, or SC-SM.G If fines are organic, add “with organic fines” to group name.H Sands with 5 to 12 %
44、fines require dual symbols:SW-SM well-graded sand with siltSW-SC well-graded sand with claySP-SM poorly graded sand with siltSP-SC poorly graded sand with clayI If soil contains $15 % gravel, add “with gravel” to group name.J If Atterberg limits plot in hatched area, soil is a CL-ML, silty clay.K If
45、 soil contains 15 to 30 % plus No. 200, add “with sand” or “with gravel,” whichever is predominant.L If soil contains $30 % plus No. 200, predominantly sand, add “sand ” “sand” to group name.M If soil contains $30 % plus No. 200, predominantly gravel, add “gravelly” to group name.N PI $ 4 and plots
46、on or above “A” line.O PI 4 or plots below “A” line.P PI plots on or above “A” line.Q PI plots below “A” line.D2487 1735. Significance and Use5.1 This standard classifies soils from any geographic location into categories representing the results of prescribed laboratorytests to determine the partic
47、le-size characteristics, the liquid limit, and the plasticity index.FIG. 1 Flow Chart for Classifying Fine-Grained Soil (50 % or More Passes No. 200 Sieve)FIG. 2 Flow Chart for Classifying Organic Fine-Grained Soil (50 % or More Passes No. 200 Sieve)D2487 1745.2 The assigning of a group name and sym
48、bol(s) along with the descriptive information required in Practice D2488 can be usedto describe a soil to aid in the evaluation of its significant properties for engineering use.5.3 The various groupings of this classification system have been devised to correlate in a general way with the engineeri
49、ngbehavior of soils. This standard provides a useful first step in any field or laboratory investigation for geotechnical engineeringpurposes.5.4 This standard may also be used as an aid in training personnel in the use of Practice D2488.5.5 This standard may be used in combination with Practice D4083 when working with frozen soils.NOTE 5Notwithstanding the statements on precision and bias contained in this standard: The precision of this test method is dependent on thecompetence of the personnel performing it and the suitability
