ASTM_D_7012_-_14.pdf

Designation:D701214Standard Test Methods forCompressive Strength and Elastic Moduli of Intact RockCore Specimens under Varying States of Stress andTemperatures1This standard is issued under the fixed designation D7012;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.1.Scope1.1 These four test methods cover the determination of thestrength of intact rock core specimens in uniaxial and triaxialcompression.MethodsAand B determine the triaxial compres-sive strength at different pressures and Methods C and Ddetermine the unconfined,uniaxial strength.1.2 Methods A and B can be used to determine the angle ofinternal friction,angle of shearing resistance,and cohesionintercept.1.3 MethodsBandDspecifytheapparatus,instrumentation,and procedures for determining the stress-axial strain and the stress-lateral strain curves,as well asYoungs modulus,E,and Poissons ratio,.These methodsmake no provision for pore pressure measurements and speci-mens are undrained(platens are not vented).Thus,the strengthvalues determined are in terms of total stress and are notcorrected for pore pressures.These test methods do not includethe procedures necessary to obtain a stress-strain curve beyondthe ultimate strength.1.4 OptionAallows for testing at different temperatures andcan be applied to any of the test methods,if requested.1.5 This standard replaces and combines the followingStandard Test Methods:D2664 Triaxial Compressive Strengthof Undrained Rock Core Specimens Without Pore PressureMeasurements;D5407 Elastic Moduli of Undrained Rock CoreSpecimens in Triaxial Compression Without Pore PressureMeasurements;D2938 Unconfined Compressive Strength ofIntact Rock Core Specimens;and D3148 Elastic Moduli ofIntact Rock Core Specimens in Uniaxial Compression.Theoriginal four standards are now referred to as Methods in thisstandard.1.5.1 Method A:TriaxialCompressiveStrengthofUndrained Rock Core Specimens Without Pore Pressure Mea-surements.1.5.1.1 Method A is used for obtaining strength determina-tions.Strain is not typically measured;therefore a stress-straincurve is not produced.1.5.2 Method B:Elastic Moduli of Undrained Rock CoreSpecimens in Triaxial Compression Without Pore PressureMeasurements.1.5.3 Method C:Uniaxial Compressive Strength of IntactRock Core Specimens.1.5.3.1 Method C is used for obtaining strength determina-tions.Strain is not typically measured;therefore a stress-straincurve is not produced.1.5.4 Method D:Elastic Moduli of Intact Rock Core Speci-mens in Uniaxial Compression.1.5.5 Option A:Temperature VariationApplies to any ofthe methods and allows for testing at temperatures above orbelow room temperature.1.6 For an isotropic material in Test Methods B and D,therelation between the shear and bulk moduli and Youngsmodulus and Poissons ratio are:G 5E211!(1)K 5E31 2 2!(2)where:G=shear modulus,K=bulk modulus,E=Youngs modulus,and=Poissons ratio.1.6.1 The engineering applicability of these equations de-creases with increasing anisotropy of the rock.It is desirable toconduct tests in the plane of foliation,cleavage or bedding andat right angles to it to determine the degree of anisotropy.It isnoted that equations developed for isotropic materials may giveonly approximate calculated results if the difference in elasticmoduli in two orthogonal directions is greater than 10%for agiven stress level.NOTE1Elastic moduli measured by sonic methods(Test MethodD2845)may often be employed as a preliminary measure of anisotropy.1These test methods are under the jurisdiction ofASTM Committee D18 on Soiland Rock and is the direct responsibility of Subcommittee D18.12 on RockMechanics.Current edition approved May 1,2014.Published June 2014.Originallyapproved in 2004.Last previous edition approved in 2013 as D7012 13.DOI:10.1520/D7012-14.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 1.7 Test Methods B and D for determining the elasticconstants do not apply to rocks that undergo significantinelastic strains during the test,such as potash and salt.Theelastic moduli for such rocks should be determined fromunload-reload cycles that are not covered by these test meth-ods.1.8 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.9 All observed and calculated values shall conform to theguidelines for significant digits and rounding established inPractice D6026.1.9.1 The procedures used to specify how data are collected/recorded or calculated,in this standard are regarded as theindustry standard.In addition,they are representative of thesignificant digits that generally should be retained.The proce-dures used do not cons