ASTM_D_2487_-_11.pdf

Designation:D248711Standard 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 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 practice describes a system for classifying mineraland organo-mineral soils for engineering purposes based onlaboratory determination of particle-size characteristics,liquidlimit,and plasticity index and shall be used when preciseclassification is required.NOTE1Use of this standard will result in a single classification groupsymbol 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 thecrosshatched area of the plasticity chart.In these two cases,a dual symbolis used,for example,GP-GM,CL-ML.When the laboratory test resultsindicate that the soil is close to another soil classification group,theborderline condition can be indicated with two symbols separated by aslash.The first symbol should be the one based on this standard,forexample,CL/CH,GM/SM,SC/CL.Borderline symbols are particularlyuseful when the liquid limit value of clayey soils is close to 50.These soilscan have expansive characteristics and the use of a borderline symbol(CL/CH,CH/CL)will alert the user of the assigned classifications ofexpansive potential.1.2 The group symbol portion of this system is based onlaboratory tests performed on the portion of a soil samplepassing the 3-in.(75-mm)sieve(see Specification E11).1.3 As a classification system,this standard is limited tonaturally occurring soils.NOTE2The group names and symbols used in this test method maybe used as a descriptive system applied to such materials as shale,claystone,shells,crushed rock,etc.See Appendix X2.1.4 This standard is for qualitative application only.NOTE3When quantitative information is required for detailed designsof important structures,this test method must be supplemented bylaboratory tests or other quantitative data to determine performancecharacteristics under expected field conditions.1.5 This standard is the ASTM version of the Unified SoilClassification System.The basis for the classification schemeis the Airfield Classification System developed by A.Casa-grande in the early 1940s.2It became known as the UnifiedSoil Classification System when several U.S.GovernmentAgencies adopted a modified version of the Airfield System in1952.1.6 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.1.7 This practice offers a set of instructions for performingone or more specific operations.This document cannot replaceeducation or experience and should be used in conjunctionwith professional judgment.Not all aspects of this practice maybe applicable in all circumstances.This ASTM standard is notintended to represent or replace the standard of care by whichthe adequacy of a given professional service must be judged,nor should this document be applied without consideration ofa projects many unique aspects.The word“Standard”in thetitle of this document means only that the document has beenapproved through the ASTM consensus process.2.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 Analysis of Fine and CoarseAggregatesC702 Practice for Reducing Samples ofAggregate to TestingSizeD420 Guide to Site Characterization for Engineering Designand Construction Purposes(Withdrawn 2011)4D422 Test Method for Particle-Size Analysis of SoilsD653 Terminology Relating to Soil,Rock,and ContainedFluids1This practice is under the jurisdiction of ASTM Committee D18 on Soil andRock and is the direct responsibility of Subcommittee D18.07 on Identification andClassification of Soils.Current edition approved May 1,2011.Published June 2011.Originallyapproved in 1966.Last previous edition approved in 2010 as D2487 10.DOI:10.1520/D2487-11.2Casagrande,A.,“Classification and Identification of Soils,”Transactions,ASCE,1948,p.901.3For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.4The last approved version of this historical standard is referenced onwww.astm.org.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100