ASTM_D_2845_-_08.pdf

Designation:D284508Standard Test Method forLaboratory Determination of Pulse Velocities and UltrasonicElastic Constants of Rock1This standard is issued under the fixed designation D2845;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.Scope*1.1 This test method describes equipment and proceduresfor laboratory measurements of the pulse velocities of com-pression waves and shear waves in rock(1)2and the determi-nation of ultrasonic elastic constants(Note 1)of an isotropicrock or one exhibiting slight anisotropy.NOTE1The elastic constants determined by this test method aretermed ultrasonic since the pulse frequencies used are above the audiblerange.The terms sonic and dynamic are sometimes applied to theseconstants but do not describe them precisely(2).It is possible that theultrasonic elastic constants may differ from those determined by otherdynamic methods.1.2 This test method is valid for wave velocity measure-ments in both anisotropic and isotropic rocks although thevelocities obtained in grossly anisotropic rocks may be influ-enced by such factors as direction,travel distance,and diam-eter of transducers.1.3 The ultrasonic elastic constants are calculated from themeasured wave velocities and the bulk density.The limitingdegree of anisotropy for which calculations of elastic constantsare allowed and procedures for determining the degree ofanisotropy are specified.1.4 The values stated in inch-pound units are to be regardedas standard.The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.1.5 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:3D653 Terminology Relating to Soil,Rock,and ContainedFluidsD2216 Test Methods for Laboratory Determination of Water(Moisture)Content of Soil and Rock by MassD3740 Practice for Minimum Requirements for AgenciesEngaged in Testing and/or Inspection of Soil and Rock asUsed in Engineering Design and ConstructionD6026 Practice for Using Significant Digits in GeotechnicalDataE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3.Terminology3.1 For common definitions of terms in this standard,referto Terminology D653.3.2 Definitions of Terms Specific to This Standard:3.2.1 compression wave velocitythe dilational wave ve-locity which is the propagation velocity of a longitudinal wavein a medium that is effectively infinite in lateral extent.It is notto be confused with bar or rod velocity.4.Summary of Test Method4.1 Details of essential procedures for the determination ofthe ultrasonic velocity,measured in terms of travel time anddistance,of compression and shear waves in rock specimensinclude requirements of instrumentation,suggested types oftransducers,methods of preparation,and effects of specimengeometry and grain size.Elastic constants may be calculatedfor isotropic or slightly anisotropic rocks,while anisotropy isreported in terms of the variation of wave velocity withdirection in the rock.1This test method is under the jurisdiction ofASTM Committee D18 on Soil andRock and is the direct responsibility of Subcommittee D18.12 on Rock Mechanics.Current edition approved July 1,2008.Published July 2008.Originally approvedin 1969.Last previous edition approved in 2005 as D2845 05.DOI:10.1520/D2845-08.2The boldface numbers in parentheses refer to the list of references at the end ofthis test method.3For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.*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 5.Significance and Use5.1 The primary advantages of ultrasonic testing are that ityields compression and shear wave velocities,and ultrasonicvalues for the elastic constants of intact homogeneous isotropicrock specimens(3).Elastic constants are not to be calculatedfor rocks having pronounced anisotropy by procedures de-scribed in this test method.The values of elastic constants oftendo not agree with those determined by static laboratorymethods or the in situ methods.Measured wave velocitieslikewise may not agree with seismic velocities,but offer goodapproximations.The ultrasonic evaluation of rock properties isuseful for preliminary prediction of sta