Designation:D5607−16StandardTestMethodforPerformingLaboratoryDirectShearStrengthTestsofRockSpecimensUnderConstantNormalForce1ThisstandardisissuedunderthefixeddesignationD5607;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope*1.1Thistestmethodestablishesrequirementsandlabora-toryproceduresforperformingdirectshearstrengthtestsonrockspecimensunderaconstantnormalload.Itincludesproceduresforbothintactrockstrengthandslidingfrictiontests,whichcanbeperformedonspecimensthatarehomogeneous,orhaveplanesofweakness,includingnaturalorartificialdiscontinuities.Examplesofanartificialdiscontinuityincludearock-concreteinterfaceoraliftlinefromaconcretepour.Discontinuitiesmaybeopen,partiallyorcompletelyhealedorfilled(thatis,clayfillingsandgouge).Onlyonediscontinuityperspecimencanbetested.Thetestisusuallyconductedintheundrainedstatewithanappliedconstantnormalload.However,aclean,opendiscontinuitymaybefreedraining,and,therefore,atestonaclean,opendiscontinuitycouldbeconsideredadrainedtest.Duringthetest,shearstrengthisdeterminedatvariousappliedstressesnormaltotheshearedplaneandatvarioussheardisplacements.Relation-shipsderivedfromthetestdataincludeshearstrengthversusnormalstressandshearstressversussheardisplacement(shearstiffness).NOTE1—Theterm“normalforce”isusedinthetitleinsteadofnormalstressbecauseoftheindefinableareaofcontactandtheminimalrelativedisplacementbetweenupperandlowerhalvesofthespecimenduringtesting.Theactualcontactareasduringtestingchange,buttheactualtotalcontactsurfaceisunmeasurable.Thereforenominalareaisusedforloadingpurposesandcalculations.NOTE2—Sincethistestmethodmakesnoprovisionforthemeasure-mentofporepressures,thestrengthvaluesdeterminedareexpressedintermsoftotalstress,uncorrectedforporepressure.1.2Thisstandardappliestohardrock,mediumrock,softrock,andcon...
