Designation:D7181−11StandardTestMethodforConsolidatedDrainedTriaxialCompressionTestforSoils1ThisstandardisissuedunderthefixeddesignationD7181;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thistestmethodcoversthedeterminationofstrengthandstress-strainrelationshipsofacylindricalspecimenofeitherintactorreconstitutedsoil.Specimensareconsolidatedandshearedincompressionwithdrainageataconstantrateofaxialdeformation(straincontrolled).1.2Thistestmethodprovidesforthecalculationofprinci-palstressesandaxialcompressionbymeasurementofaxialload,axialdeformation,andvolumetricchanges.1.3ThistestmethodprovidesdatausefulindeterminingstrengthanddeformationpropertiessuchasMohrstrengthenvelopes.Generally,threespecimensaretestedatdifferenteffectiveconsolidationstressestodefineastrengthenvelope.1.4Ifthistestmethodisusedoncohesivesoil,atestmaytakeweekstocomplete.1.5Thedeterminationofstrengthenvelopesandthedevel-opmentofrelationshipstoaidininterpretingandevaluatingtestresultsarebeyondthescopeofthistestmethodandmustbeperformedbyaqualified,experiencedprofessional.1.6AllobservedandcalculatedvaluesshallconformtotheguidelinesforsignificantdigitsandroundingestablishedinPracticeD6026.1.6.1Themethodsusedtospecifyhowdataarecollected,calculated,orrecordedinthisstandardareregardedastheindustrystandard.Inaddition,theyarerepresentativeofthesignificantdigitsthatgenerallyshouldberetained.Theproce-duresuseddonotconsidermaterialvariations,purposeforobtainingthedata,specialpurposestudiesoranyconsiderationoftheenduse.Itisbeyondthescopeofthistestmethodtoconsidersignificantdigitsusedinanalysismethodsforengi-neeringdesign.1.7Units—ThevaluesstatedinSIunitsaretoberegardedasstandard.Theinch-poundunitsgiveninparenthesesaremathematicalconversions,whichareprovidedforinformationpurposesonlyandareno...
