ASTM_D_4394_-_08.pdf

Designation:D439408Standard Test Method forDetermining In Situ Modulus of Deformation of Rock MassUsing Rigid Plate Loading Method1This standard is issued under the fixed designation D4394;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 covers the preparation,equipment,testprocedure,and data reduction for determining in situ modulusof deformation of a rock mass using the rigid plate loadingmethod.1.2 This test method is designed to be conducted in an aditor small underground chamber;however,with suitable modi-fications it could be conducted at the surface.1.3 This test method is usually conducted parallel or per-pendicular to the anticipated axis of thrust,as dictated by thedesign load.1.4 Time dependent tests can be performed but are to bereported in another standard.1.5 Observed and calculated values shall conform to theguidelines for significant digits and rounding established inPractice D6026.1.5.1 The method used to specify how data are collected,calculated,or recorded in this standard is not directly related tothe accuracy to which the data can be applied in design or otheruses,or both.How one applies the results obtained using thisstandard is beyond its scope.1.6 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.1.7 The references appended to this standard contain furtherinformation on this test method.1.8 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 requirements prior to use.For specificprecaution statements,see Section 8.2.Referenced Documents2.1 ASTM Standards:2D653 Terminology Relating to Soil,Rock,and ContainedFluidsD2113 Practice for Rock Core Drilling and Sampling ofRock for Site ExplorationD4395 Test Method for Determining In Situ Modulus ofDeformation of Rock Mass Using Flexible Plate LoadingMethodD4403 Practice for Extensometers Used in RockD4879 Guide for Geotechnical Mapping of Large Under-ground Openings in RockD5079 Practices for Preserving and Transporting Rock CoreSamplesD5434 Guide for Field Logging of Subsurface Explorationsof Soil and RockD6026 Practice for Using Significant Digits in GeotechnicalDataD6032 Test Method for Determining Rock Quality Designa-tion(RQD)of Rock Core3.Terminology3.1 For terminology used in this test method,refer toTerminology,D653.3.2 Definitions of Terms Specific to This Standard:3.2.1 deflectionmovement of the rigid plate,mortar pad,or rock in response to and in the same direction as the appliedload.3.2.2 loadtotal force acting on the rock face.3.2.3 peak-to-peak modulus of deformationthe slope ofthe stress-strain curve line connecting the peaks of the curvesobtained from successive pressure cycles(see Fig.1).3.2.4 recovery modulus of deformationthe tangent modu-lus of the unloading stress-strain curve.This modulus isusually higher than the other moduli and is used in calculationswhere unloading conditions exist.The difference between the1This 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 August 2008.Originallyapproved in 1984.Last previous edition approved in 2004 as D4394 04.DOI:10.1520/D4394-08.2For 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 tangent and recovery moduli indicates that materials capacityof hysteresis or energy dissipation capabilities(see Fig.2).3.2.5 rigid plateplate with deflection of less than 0.0001in.(0.0025 mm)from center to edge of plate,when maximumload is applied.3.2.6 secant modulus of deformationthe slope of thestress-strain curve between zero stress and a specified stress.This modulus should be used for the load steps from zero to thedesired load(see Fig.2).3.2.7 tangent modulus of deformationthe slope of thestress-strain curve obtained over the segment of the loadingcurve judged by the investigator as the most representative ofelastic response.It neglects the end effects of the curve and isbetter suited to small stress changes.The ratio between thesecant modulus and the tangent modulus can be