1、Designation:D472908Standard Test Method forIn Situ Stress and Modulus of Deformation Using FlatjackMethod1This standard is issued under the fixed designation D4729;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revi
2、sion.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 The flatjack test measures stress at a rock surface.Themodulus of deformation and the long-term deformationalproperties(creep)may a
3、lso be evaluated.1.2 All observed and calculated values shall conform to theguidelines for significant digits and rounding established inPractice D6026.1.2.1 The method used to specifiy how data are collected,calculated,or recorded in this standard is not directly related tothe accuracy to which the
4、 data can be applied in design or otheruses,or both.How one applies the results obtained using thisstandard is beyond its scope.1.3 LimitationThe flatjack test measures the averagestress normal to the surface of the test chamber.Undisturbedstress levels must be determined by theoretical interpretati
5、onsof these data.1.4 Assumptions and Factors Influencing the Data:1.4.1 The stress relief is assumed to be an elastic,reversibleprocess.In nonhomogeneous or highly fractured materials,thismay not be completely true.1.4.2 The equations assume that the rock mass is isotropicand homogeneous.Anisotropic
6、 effects may be estimated bytesting in different orientations.1.4.3 The flatjack is assumed to be 100%efficient.Thedesign and size requirements of 7.1 were determined to satisfythis requirement to within a few percent.1.4.4 The jack is assumed to be aligned with the principalstresses on the surface
7、of the opening.Shear stresses are notcanceled by jack pressure.Orientating the tests in threedirections in each plane tested prevents the misalignment frombeing excessive for at least one of the tests.1.5 The values stated in inch-pound units are to be regardedas standard.The values given in parenth
8、eses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.1.6 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 saf
9、ety and health practices and determine the applica-bility of regulatory requirements prior to use.2.Referenced Documents2.1 ASTM Standards:2D653 Terminology Relating to Soil,Rock,and ContainedFluidsD2113 Practice for Rock Core Drilling and Sampling ofRock for Site ExplorationD3740 Practice for Minim
10、um Requirements for AgenciesEngaged in Testing and/or Inspection of Soil and Rock asUsed in Engineering Design and ConstructionD5720 Practice for Static Calibration of ElectronicTransducer-Based Pressure Measurement Systems forGeotechnical PurposesD6026 Practice for Using Significant Digits in Geote
11、chnicalDataD6027 Practice for Calibrating Linear Displacement Trans-ducers for Geotechnical Purposes(Withdrawn 2013)33.Terminology3.1 For terminology used in this test method,refer toTerminology D653.3.2 Definitions of Terms Specific to This Standard:3.2.1 cancellation pressurethe pressure in the fl
12、atjackrequired to return the rock to its initial position.3.2.2 skin stressthe tangential stress at the surface of anopening.3.2.3 undisturbed stressthe stress field existing in a rockmass prior to excavation of an opening.1This test method is under the jurisdiction ofASTM Committee D18 on Soil andR
13、ock and is the direct responsibility of Subcommittee D18.12 on Rock Mechanics.Current edition approved July 1,2008.Published July 2008.Originally approvedin 1987.Last previous edition approved in 2004 as D4729 04.DOI:10.1520/D4729-08.2For referenced ASTM standards,visit the ASTM website,www.astm.org
14、,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.*A Summary of Changes section appears at the end
15、 of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 4.Summary of Test Method4.1 The in situ stress in the rock mass is relieved by cuttinga slot into the rock perpendicular to the surface of the test adit.The deformation caus
16、ed by this stress relief is measured.Ahydraulic flatjack is placed into the slot and is pressurized untilthe above-measured displacement is canceled.This reappliedstress is approximately equal to the stress in the rock mass atthe test location in a direction perpendicular to the plane of thejack.The deformational characteristics of the rock mass areevaluated by incrementally loading the flatjack and measuringthe deformation.5.Significance and Use5.1 Tests in Orthogonal DirectionsThe flatjack mos