Designation:D3080/D3080M−11StandardTestMethodforDirectShearTestofSoilsUnderConsolidatedDrainedConditions1ThisstandardisissuedunderthefixeddesignationD3080/D3080M;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope*1.1Thistestmethodcoversthedeterminationofthecon-solidateddrainedshearstrengthofonespecimenofasoilmaterialunderdirectshearboundaryconditions.Thespecimenisdeformedatacontrolledrateonornearasingleshearplanedeterminedbytheconfigurationoftheapparatus.1.2Shearstressesanddisplacementsarenonuniformlydis-tributedwithinthespecimen.Anappropriateheightcannotbedefinedforcalculationofshearstrains.Therefore,stress-strainrelationshipsoranyassociatedquantitysuchastheshearmodulus,cannotbedeterminedfromthistest.1.3Thedeterminationofstrengthenvelopesandthedevel-opmentofcriteriatointerpretandevaluatetestresultsarelefttotheengineerorofficerequestingthetest.1.4Theresultsofthetestmaybeaffectedbythepresenceofcoarse-grainedsoilorrockparticles,orboth,(seeSection7).1.5Testconditions,includingnormalstressandmoistureenvironment,shouldbeselectedtorepresentthefieldcondi-tionsbeinginvestigated.Therateofshearingmustbeslowenoughtoensuredrainedconditions.1.6Generally,threeormoretestsareperformedonspeci-mensfromonesoilsample,eachunderadifferentnormalload,todeterminetheeffectsuponshearresistanceanddisplace-ment.ResultsfromatestseriesarecombinedtodeterminestrengthpropertiessuchasMohrstrengthenvelopes.Interpre-tationofmultipletestsrequiresengineeringjudgmentandisbeyondthescopeofthistestmethod.Thistestmethodpertainstotherequirementsforasingletest.1.7Theremaybeinstanceswhenthegapbetweentheshearboxhalvesshouldbeincreasedtoaccommodatesandsizedparticlesgreaterthanthespecifiedgap.Presentlythereisinsufficientinformationavailableforspecifyingthegapdimen-sionbasedonparticlesizedistribution.1...
