Designation:D2938–95(Reapproved2002)StandardTestMethodforUnconfinedCompressiveStrengthofIntactRockCoreSpecimens1ThisstandardisissuedunderthefixeddesignationD2938;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(e)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thistestmethodspecifiestheapparatus,instrumenta-tion,andproceduresfordeterminingunconfinedcompressivestrengthofintactrockcorespecimens.1.2Thevaluesstatedininch-poundunitsaretoberegardedasthestandard.TheSIvaluesgiveninparenthesesareforinformationonly.1.3Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesanddeterminetheapplica-bilityofregulatorylimitationspriortouse.2.ReferencedDocuments2.1ASTMStandards:D2216TestMethodforLaboratoryDeterminationofWater(Moisture)ContentofSoilandRock2D4543PracticeforPreparingRockCoreSpecimensandDeterminingDimensionalandShapeTolerances2E4PracticesforLoadVerificationofTestingMachines3E122PracticeforChoiceofSampleSizetoEstimatetheAverageQualityofaLotorProcess43.SummaryofTestMethod3.1Arockcoresampleiscuttolengthandtheendsaremachinedflat.Thespecimenisplacedinaloadingframeand,ifrequired,heatedtothedesiredtesttemperature.Axialloadiscontinuouslyincreasedonthespecimenuntilpeakloadandfailureareobtained.4.SignificanceandUse4.1Unconfinedcompressivestrengthofrockisusedinmanydesignformulasandissometimesusedasanindexpropertytoselecttheappropriateexcavationtechnique.4.2Thestrengthofrockcoresmeasuredinthelaboratoryusuallydonotaccuratelyreflectlarge-scaleinsitupropertiesbecausethelatterarestronglyinfluencedbyjoints,faults,inhomogeneities,weaknessplanes,andotherfactors.There-fore,laboratoryvaluesforintactspecimensmustbeemployedwithproperjudgementinengineeringapplications.5.Apparatus5.1LoadingDevice,ofsufficien...
