1、Designation:D 2487-00Standard Practice forClassification of Soils for Engineering Purposes(UnifiedSoil Classification System)This standard is issued under the fixed designation D 2487;the number immediately following the designation indicates the year oforiginal adoption or.in the case of revision.t
2、he year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon(e)indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1.ScopeSoil Classification System when se
3、veral U.S.Government1.1 This practice describes a system for classifying mineralAgencies adopted a modified version of the Airfield System inand organo-mineral soils for engineering purposes based on1952.laboratory determination of particle-size characteristics,liquid1.6 This standard does not purpo
4、rt to address all of thelimit,and plasticity index and shall be used when precisesafety concerns,if any,associated with its use.It is theclassification is required.responsibility of the user of this standard to establish appro-priate safery and health practices and determine the applica-NorE 1-Use o
5、f this standard will result in a single classification groupbility of regulatory limitations prior to use.symbol and group name except when a soil contains 5 to 12 fines orwhen the plot of the liquid limit and plasticity index values falls into the1.7 This practice offers a set of instructions for p
6、erformingcrosshatched area of the plasticity chart.In these two cases,a dual symbolone or more specific operations.This document cannot replaceis used,for example,GP-GM,CL-ML.When the laboratory test resultseducation or experience and should not be used in conjunctionindicate that the soil is close
7、to another soil classification group,thewith professional judgment.Not all aspects of this practice mayborderline condition can be indicated with two symbols separated by abe applicable in all circumstances.This ASTM standard is notslash.The first symbol should be the one based on this standard,fori
8、ntended to represent or replace the standard of care by whichexample,CL/CH,GM/SM,SC/CL.Borderline symbols are particularlythe adequacy of a given professional service must be judged,useful when the liquid limit value of clayey soils is close to 50.These soilscan have expansive characteristics and th
9、e use of a borderline symbolnor should this document be applied without consideration of(CL/CH,CH/CL)will alert the user of the assigned classifications ofa projects many unique aspects.The word Standardin theexpansive potential.title of this document means only that the document has been1.2 The gro
10、up symbol portion of this system is based onapproved through the ASTM consensus process.laboratory tests performed on the portion of a soil sample2.Referenced Documentspassing the 3-in.(75-mm)sieve(see Specification E 11).1.3 As a classification system,this standard is limited to2.1 ASTM Standards:C
11、 117 Test Method for Materials Finer Than 75-um(No.naturally occurring soils.200)Sieve in Mineral Aggregates by Washing?NorE 2-The group names and symbols used in this test method mayC 136 Test Method for Sieve Analysis of Fine and Coarsebe used as a descriptive system applied to such materials as s
12、hale,Aggregates3claystone.shells,crushed rock.ete.See Appendix X2.C 702 Practice for Reducing Field Samples of Aggregate to1.4 This standard is for qualitative application only.Testing SizeNorE 3-When quantitative information is required for detailed de-D 420 Guide to Site Characterization for Engin
13、eering,De-signs of important structures,this test method must be supplemented bysign and Construction Purposeslaboratory tests or other quantitative data to determine performanceD421 Practice for Dry Preparation of Soil Samples forcharacteristics under expected field conditions.Particle-Size Analysi
14、s and Determination of Soil Con-1.5 This standard is the ASTM version of the Unified Soilstants4Classification System.The basis for the classification schemeD 422 Test Method for Particle-Size Analysis of Soils4is the Airfield Classification System developed by A.Casa-D 653 Terminology Relating to S
15、oil,Rock,and Containedgrande in the early 1940s.2 It became known as the UnifiedFluidsD 1140 Test Method for Amount of Material in Soils Finerthan the No.200(75-um)SieveThis standard is under the jurisdiction of ASTM Committee D-18 on Soil andRock and is the direct responsibility of Subcommittee D18
16、.07 on Identification andD 2216 Test Method for Laboratory Determination of WaterClassification of Soils.(Moisture)Content of Soil and RockCurrent edition approved March 10,2000.Published May 2000.Originallypublished as D 2487-66 T.Last previous edition D 2487-98.2 Casagrande,A.Classification and Id
17、entification of Soils,Transactions,3 Annual Book of ASTM Standards,Vol 04.02.ASCE.1948.p.901.Annual Book of ASTM Standards,Vol 04.08.*A Summary of Changes section appears at the end of this standard.CopyrightASTM.100 Barr Harbor Drive.West Conshohocken,PA 19428-2959.United States.COPYRIGHT 2000 Amer
18、ican Society for Testing and MaterialsInformation Handling Services,20004D2487D2217 Practice for Wet Preparation of Soil Samples for3.1.3 organic clay-a clay with sufficient organic content toParticle-Size Analysis and Determination of Soil Con-influence the soil properties.For classification,an org
19、anic claystantsis a soil that would be classified as a clay except that its liquidD 2488 Practice for Description and Identification of Soilslimit value after oven drying is less than 75 of its liquid limit(Visual-Manual Procedure)value before oven drying.D3740 Practice for Minimum Requirements for
20、Agencies3.1.4 organic silt-a silt with sufficient organic content toEngaged in the Testing and/or Inspection of Soil and Rockinfluence the soil properties.For classification,an organic siltas Used in Engineering Design and Construction3is a soil that would be classified as a silt except that its liq
21、uidD 4083 Practice for Description of Frozen Soils(Visual-limit value after oven drying is less than 75 of its liquid limitManual Procedure)value before oven drying.D4318 Test Method for Liquid Limit,Plastic Limit,and3.1.5 peat-a soil composed of vegetable tissue in variousPlasticity Index of Soils4
22、stages of decomposition usually with an organic odor,aD4427 Classification of Peat Samples by Laboratory Test-dark-brown to black color,a spongy consistency,and a textureing4ranging from fibrous to amorphous.E 11 Specification for Wire-Cloth Sieves for Testing Pur-3.1.6 sand-particles of rock that w
23、ill pass a No.4(4.75-posesmm)sieve and be retained on a No.200(75-um)U.S.standard3.Terminologysieve with the following subdivisions:Coarse-passes No.4(4.75-mm)sieve and retained on No.3.1 Definitions-Except as listed below,all definitions are10(2.00-mm)sieve,in accordance with Terminology D 653.Medi
24、um-passes No.10(2.00-mm)sieve and retained onNorE 4-For particles retained on a 3-in.(75-mm)U.S.standard sieve,No.40(425-um)sieve,andthe following definitions are suggested:Fine-passes No.40(425-um)sieve and retained on No.Cobbles-particles of rock that will pass a 12-in.(300-mm)square200(75-um)siev
25、e.opening and be retained on a 3-in.(75-mm)U.S.standard sieve,and3.1.7 silt-soil passing a No.200(75-um)U.S.standardBoulders-particles of rock that will not pass a 12-in.(300-mm)squaresieve that is nonplastic or very slightly plastic and that exhibitsopening.little or no strength when air dry.For cl
26、assification,a silt is a3.1.1 clay-soil passing a No.200(75-um)U.S.standardfine-grained soil,or the fine-grained portion of a soil,with asieve that can be made to exhibit plasticity(putty-like proper-plasticity index less than 4 or if the plot of plasticity indexties)within a range of water contents
27、 and that exhibitsversus liquid limit falls below the“A”line.considerable strength when air dry.For classification,a clay is3.2 Definitions of Terms Specific to This Standard:a fine-grained soil,or the fine-grained portion of a soil,with a3.2.1 coefficient of curvature,Cc-the ratio(D3o)21plasticity
28、index equal to or greater than 4,and the plot of(DioX D6o),where D60.D3o.and Dio are the particle sizesplasticity index versus liquid limit falls on or above the Acorresponding to 60,30,and 10%finer on the cumulativeline.particle-size distribution curve,respectively.3.1.2 gravel-particles of rock th
29、at will pass a 3-in.(75-3.2.2 coefficient of uniformity,Cu-the ratio De/D1o wheremm)sieve and be retained on a No.4(4.75-mm)U.S.standardD6o and Do are the particle diameters corresponding to 60 andsieve with the following subdivisions:10%finer on the cumulative particle-size distribution curve,Coars
30、e-passes 3-in.(75-mm)sieve and retained on 34-in.respectively.(19-mm)sieve,and4.SummaryFine-passes 34-in.(19-mm)sieve and retained on No.4(4.75-mm)sieve.4.1 As illustrated in Table 1,this classification systemidentifies three major soil divisions:coarse-grained soilsfine-grained soils,and highly org
31、anic soils.These three divi-5 Annual Book of ASTM Standards,Vol 04.09.sions are further subdivided into a total of 15 basic soil groups.Annual Book of ASTM Standards,Vol 14.02TABLE 1 Soil Classification ChartSoil ClassificationCriteria for Assigning Group Symbols and Group Names Using Laboratory Tes
32、tsAGroup SymbolGroup NameCOARSE-GRAINEDGravelsClean GravelsCu4andGWWell-graded gravelSOILS1Cc3CMore than 50More than 50%ofLess than 5%finesCu Cc39200 sieveretained on No.4sieveGravels with FinesFines classify as MLGMSilty gravelor MHMore than 12%finesFines classify as CL or,urule:1GCClayey graveCHSa
33、ndsClean SandsCu=6 andSWWell-graded sand1Cc392COPYRIGHT 2000 American Society for Testing and MaterialsInformation Handling Services,2000D2487TABLE 1 ContinuedSoil ClassificationCriteria for Assigning Group Symbols and Group Names Using Laboratory TestsGroup SymbolGroup Name50%or more ofLess than 5%
34、finesCu Cc3fraction passes No.4Sands with FinesFines classify as MLSMSilty sandF,G,Hsieveor MHMore than 12%fines Fines classify as CL orSCClayey sandFCHFINE-GRAINEDSilts and ClaysinorganicPl 7 and plots on orCLLean clay,MSOILSabove A line50%or more passesLiquid limit less thanPI0.75Liquid limit-not
35、driedOLOrganic siltKL MOSilts and ClaysinorganicPI plots on or aboveCHFat clayK L MAlineLiquid limit 50 or morePI plots below A lineMHElastic siltKLMorganicLiquid limit-ovenOHOrganic clayKLMPdried 0.75Liquid limit-not driedOrganic siltKLMHIGHLY ORGANICPrimarily organic matter,dark in color,and organ
36、ic odorPTPeatSOILS Based on the material passing the 3-in.(75-mm)sieve.If field sample contained cobbles or boulders,or both,add with cobbles or boulders,or both to group name.cCu=D60/D10 Cc=(D30)2/D10 X D60 If soil contains 15%sand,add with sand to group name.E Gravels with 5 to 12%fines require du
37、al symbols:GW-GM well-graded gravel with siltGW-GC well-graded gravel with clayGP-GM poorly graded gravel with siltGP-GC poorly graded gravel with clayF 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.If soil contains=15%gravel,ad
38、d with gravel to group name.Sands with 5 to 12%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 clay If Atterberg limits plot in hatched area,soil is a CL-ML,silty clay.If soil contains 15 to 29
39、%plus No.200,add with sand or with gravel,whichever is predominant.If soil contains 30%plus No.200,predominantly sand,add sand to group name.M If soil contains 30%plus No.200,predominantly gravel,add gravelly to group name.NPI 2 4 and plots on or above A line.PI 4 or plots below A line.PPI plots on
40、or above A line.PI plots below A line.4.2 Based on the results of visual observations and pre-any field or laboratory investigation for geotechnical engineer-scribed laboratory tests,a soil is catalogued according to theing purposes.basic soil groups,assigned a group symbol(s)and name,and5.4 This st
41、andard may also be used as an aid in trainingthereby classified.The flow charts,Fig.I for fine-grained soils,personnel in the use of Practice D 2488.and Fig.3 for coarse-grained soils,can be used to assign the5.5 This standard may be used in combination with Practiceappropriate group symbol(s)and na
42、me.D 4083 when working with frozen soils.5.Significance and UseNoTE 5-Notwithstanding the statements on precision and bias con-tained in this standard:The precision of this test method is dependent on5.1 This standard classifies soils from any geographic loca-the competence of the personnel performi
43、ng it and the suitability of thetion into categories representing the results of prescribedequipment and facilities used.Agencies that meet the criteria of Practicelaboratory tests to determine the particle-size characteristics,D 3740 are generally considered capable of competent and objectivethe li
44、quid limit,and the plasticity index.testing.Users of this test method are cautioned that compliance withPractice D 3740 does not in itself assure reliable testing.Reliable testing5.2 The assigning of a group name and symbol(s)alongdepends on several factors;Practice D 3740 provides a means forwith t
45、he descriptive information required in Practice D 2488evaluating some of those factors.can be used to describe a soil to aid in the evaluation of itssignificant properties for engineering use.6.Apparatus5.3 The various groupings of this classification system have6.1 In addition to the apparatus that
46、 may be required forbeen devised to correlate in a general way with the engineeringobtaining and preparing the samples and conducting thebehavior of soils.This standard provides a useful first step inprescribed laboratory tests,a plasticity chart,similar to Fig.4,3COPYRIGHT 2000 American Society for
47、 Testing and MaterialsInformation Handling Services,20004D2487GROUPSYMBOLGROUP NAME30%plus No.2007 and plots-CL415-29%plu1Mo.200-sand gravelLean clay with sandon or abovesand gravel-Lean clay with gravel30%plus No.20015%gravel-Sandy lean cl%wnd%g时awel15%9raw15%ngSandy lean clay with gravelGravelly l
48、ean clay15%sandGravelly lean clay with sand30%plus N6.20015%plus No.200-Silty clay4SPI7 and-CL-ML1529%plu5No.200-%sand 2%gravel-Silty clay with sandplots on or abovesand%sand 2%gravel-gravelSalty clay with gravelA-line230%plus No.20015%gravelSandy silty claysand gravel-=之15%g￥n15%sand-Sandy silty cl
49、ay with graveiGravelly silty clay套15%andGravelly silty clay with sandLL5030%plus No.20015%plus No.200-SultPI4 or plots-ML15 29%plus No.200%sand 2%gravel-Silt with sandbelow*“A-line30%plus No.200P%nd%gravel-、15%gra+15%9a￥Sandy silt with gravel网Gravelly siltLL-ovendriedGravelly silt with sand075LL-not
50、 driedSee figure 1b30%plus No.20015%plus No.200-Fat clayPI plots on or-CH415-29%plus No.200%and2%gravelFat clay with sanda0￥e“Ahnesand gravel-Fat clay with gravel=230%plu5No.200%nd%gave-15%gravelSandy fat clav215%9rawe-Sandy fat clay with gravel=15%andGravelly fat clay=t5%sandGravelly fat clay with
51、sand30%plus No.20015%plus No.200-Ela时tic siltPI plots below-MH1529%plus No.200LL50之多und之%rvElastic silt with sandr%and%gravel、%nd%gravel-Elastic silt withgrave30%phuNo.200Sandy elasstie saltSandy elastic silt with gravel套Gravelly elastic silLL-ovendried15%sandGravelly elastic silt with sandOrganicLL
52、-not dried0.75】一=0HSee figure 1bFIG.1 Flow Chart for Classifying Fine-Grained Soil(50%or More Passes No.200 Sieve)and a cumulative particle-size distribution curve,similar to Fig.provide 150 g to 200 g of soil finer than the No.40(425-um)5,are required.sieve.NorE 6-The Uline shown on Fig.4 has been
53、empirically deter-7.4 If the field sample or test specimen is smaller than themined to be the approximate upper limitfor natural soils.It is a goodminimum recommended amount,the report shall include ancheck against erroneous data,and any test results that plot above or to theappropriate remark.left
54、of it should be verified.8.Classification of Peat7.Sampling8.1 A sample composed primarily of vegetable tissue in7.1 Samples shall be obtained and identified in accordancevarious stages of decomposition and has a fibrous to amor-with a method or methods,recommended in Guide D 420 or byphous texture,
55、a dark-brown to black color,and an organic odorother accepted procedures.should be designated as a highly organic soil and shall be7.2 For accurate identification,the minimum amount of testclassified as peat,PT,and not subjected to the classificationsample required for this test method will depend o
56、n which ofprocedures described hereafter.the laboratory tests need to be performed.Where only the8.2 If desired,classification of type of peat can be per-particle-size analysis of the sample is required,specimensformed in accordance with Classification D 4427having the following minimum dry weights
57、are required:Maximum Particle Size9.Preparation for ClassificationMinimum Specimen Size.Sieve OpeningDry Weight9.1 Before a soil can be classified according to this standard,4.75mm(No.4)100g(0.251b)9.5mm%in.)200g(0.51b)generally the particle-size distribution of the minus 3-in.19.0mm(%in)1.0kg(2.2b)
58、(75-mm)material and the plasticity characteristics of the minus38.1mm(12in.)8.0kg(18bNo.40(425-um)sieve material must be determined.See 9.875.0mm(3in.60.0kg(132bfor the specific required tests.Whenever possible,the field samples should have weights9.2 The preparation of the soil specimen(s)and the t
59、estingtwo to four times larger than shown.for particle-size distribution and liquid limit and plasticity7.3 When the liquid and plastic limit tests must also beindex shall be in accordance with accepted standard proce-performed,additional material will be required sufficient todures.Two procedures f
60、or preparation of the soil specimens forCOPYRIGHT 2000 American Society for Testing and MaterialsInformation Handling Services,20004D2487GROUP SYMBOLGROUP NAME30%plus No.200=15%plus No.200Organic clay15-29%plus No.200%sand%gravelOrganic clay with sand%sand4 and plots onr%sand%gravel-15%gravel-Sandy
61、organic clayor above“a-line=30%plus No.200215%gravelSandy organic clay with gravelsand%gravel-15%sandGravelly organic clay with sandOL￥30%plus No.200=15%plus No.200Organic silt=15-29%plus No.200%sand2%graelOrganic silt with sand%sand%gravelOrganic silt with gravelPI4 or plotsP%sand%gravel15%gravelSa
62、ndy organic siltbelowA-line=230%plus No.200.15%gravelSandy organic silt with gravelsand gravel15%sand-Gravelly organic silt215%sand-Gravelly organic silt with sand30%plus No.200-=15%plus No.200Organic clay=1529%plus No.200=%sand%gravelOrganic clay with sand%sand gravelOrganic clay with gravelPlots o
63、n or%sand 2%gravel-15%gravelSandy organic clayabove A-line=230%plus No.200+15%9 ravelSandy organic clay with gravel%sand gravel-15%sand-Gravelly organic clay=15%andGravelly organic clay with sandOH30%plus No.200-=15%plus No.200Organic silt1529%plus No.200%sand%gravelOrganic silt with sandsand%gravel
64、Organic silt with gravelPlots below%sand gravel15%gravelSandy organic silt“a-line=30%plus No.200=15%gravelSandy organic silt with gravel=%sand%gra￥el=15%andGravelly organic silt15%andGravelly organic silt with sandFIG.2 Flow Chart for Classifying Organic Fine-Grained Soil(50%or More Passes No.200 Si
65、eve)testing for soil classification purposes are given in Appendixes9.8.2 For soils estimated to contain 5 to 15%fines.aX3 and X4.Appendix X3 describes the wet preparation methodcumulative particle-size distribution curve,as described inand is the preferred method for cohesive soils that have never9
66、.8.1,is required,and the liquid limit and plasticity index aredried out and for organic soils.required.9.3 When reporting soil classifications determined by this9.8.2.1 If sufficient material is not available to determine thestandard,the preparation and test procedures used shall beliquid limit and
67、plasticity index,the fines should be estimatedreported or referenced.to be either silty or clayey using the procedures described in9.4 Although the test procedure used in determining thePractice D 2488 and so noted in the report.particle-size distribution or other considerations may require a9.8.3 F
68、or soils estimated to contain 15 or more fines,ahydrometer analysis of the material,a hydrometer analysis isdetermination of the percent fines,percent sand,and percentnot necessary for soil classification.gravel is required,and the liquid limit and plasticity index are9.5 The percentage(by dry weigh
69、t)of any plus 3-in.required.For soils estimated to contain 90%fines or more,the(75-mm)material must be determined and reported as auxiliarypercent fines,percent sand,and percent gravel may be esti-information.mated using the procedures described in Practice D 2488 and9.6 The maximum particle size sh
70、all be determined(mea-so noted in the report.sured or estimated)and reported as auxiliary information.9.7 When the cumulative particle-size distribution is re-10.Preliminary Classification Procedurequired,a set of sieves shall be used which include the10.1 Class the soil as fine-grained if 50%or mor
71、e by dryfollowing sizes(with the largest size commensurate with theweight of the test specimen passes the No.200(75-um)sievemaximum particle size)with other sieve sizes as needed orand follow Section 3.1.2.required to define the particle-size distribution:10.2 Class the soil as coarse-grained if mor
72、e than 50%by3-in.(75-mm)dry weight of the test specimen is retained on the No.20034-in.(19.0-mm(75-um)sieve and follow Section 12.No.4(4.75-mm)No.10(2.00-mm)11.Procedure for Classification of Fine-Grained SoilsNo.40(425-um)No.200(75-um)(50%or more by dry weight passing the No.200(75-um)sieve)9.8 The
73、 tests required to be performed in preparation forclassification are as follows:11.1 The soil is an inorganic clay if the position of the9.8.1 For soils estimated to contain less than 5%fines,aplasticity index versus liquid limit plot,Fig.4,falls on or aboveplot of the cumulative particle-size distr
74、ibution curve of thethe Aline,the plasticity index is greater than 4,and thefraction coarser than the No.200(75-um)sieve is required.Apresence of organic matter does not influence the liquid limit assemi-log plot of percent passing versus partical-size or sievedetermined in 11.3.2.size/sieve number is plotted as shown in Fig.5.Nore 7-The plasticity index and liquid limit are determined on theCOPYRIGHT 2000 American Society for Testing and MaterialsInformation Handling Services,2000