1、Designation: D7012 141Standard 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
2、 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.1NOTEEditorially corrected legend for Eq 3 in August 2017.1. Scope1.1 These fou
3、r 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
4、 determine the angle ofinternal friction, angle of shearing resistance, and cohesionintercept.1.3 Methods B and D specify the apparatus,instrumentation, and procedures for determining the stress-axial strain and the stress-lateral strain curves, as well asYoungs modulus, E, and Poissons ratio, . The
5、se 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-str
6、ain 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 Wit
7、hout 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. Theorigin
8、al four standards are now referred to as Methods in thisstandard.1.5.1 Method A: Triaxial Compressive Strength ofUndrained 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-str
9、aincurve 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
10、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
11、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-crea
12、ses 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 give1These test methods are under the jurisdictio
13、n 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/D7012-14E01.*A Summary of Changes sec
14、tion appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision o
15、n Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1only approximate calculated results if the difference in elasticmoduli in two orthogonal directions is greater than 10 % for agiv
16、en stress level.NOTE 1Elastic moduli measured by sonic methods (Test MethodD2845) may often be employed as a preliminary measure of anisotropy.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
17、 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 sha
18、ll 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 g
19、enerally should be retained. The proce-dures used do not consider material variation, purpose forobtaining the data, special purpose studies, or any consider-ations for the users objectives; and it is common practice toincrease or reduce significant digits of reported data to becommensurate with the
20、se considerations. It is beyond the scopeof this standard to consider significant digits used in analyticalmethods for engineering design.1.10 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
21、 establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.1.11 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDe
22、velopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D653 Terminology Relating to Soil, Rock, and ContainedFluidsD2216 Test Methods for Laboratory Determination o
23、f Water(Moisture) Content of Soil and Rock by MassD2845 Test Method for Laboratory Determination of PulseVelocities and Ultrasonic Elastic Constants of Rock(Withdrawn 2017)3D3740 Practice for Minimum Requirements for AgenciesEngaged in Testing and/or Inspection of Soil and Rock asUsed in Engineering
24、 Design and ConstructionD4543 Practices for Preparing Rock Core as Cylindrical TestSpecimens and Verifying Conformance to Dimensionaland Shape Tolerances (Withdrawn 2017)3D6026 Practice for Using Significant Digits in GeotechnicalDataE4 Practices for Force Verification of Testing MachinesE122 Practi
25、ce for Calculating Sample Size to Estimate, WithSpecified Precision, the Average for a Characteristic of aLot or Process2.2 ASTM Adjunct:4Triaxial Compression Chamber Drawings (3)3. Terminology3.1 Definitions:3.1.1 For definitions of common technical terms in thisstandard, refer to Terminology D653.
26、4. Summary of Test Method4.1 A rock core specimen is cut to length and the ends aremachined flat. The specimen is placed in a loading frame andif necessary, placed in a loading chamber and subjected toconfining pressure. For a specimen tested at a differenttemperature, the test specimen is heated or
27、 cooled to thedesired test temperature prior to the start of the test. The axialload on the specimen is then increased and measured continu-ously. Deformation measurements are not obtained for Meth-ods A and C, and are measured as a function of load until peakload and failure are obtained for Method
28、s B and D.5. Significance and Use5.1 The parameters obtained from Methods A and B are interms of undrained total stress. However, there are some caseswhere either the rock type or the loading condition of theproblem under consideration will require the effective stress ordrained parameters be determ
29、ined.5.2 Method C, uniaxial compressive strength of rock is usedin many design formulas and is sometimes used as an indexproperty to select the appropriate excavation technique. Defor-mation and strength of rock are known to be functions ofconfining pressure. Method A, triaxial compression test, isc
30、ommonly used to simulate the stress conditions under whichmost underground rock masses exist. The elastic constants(Methods B and D) are used to calculate the stress anddeformation in rock structures.5.3 The deformation and strength properties of rock coresmeasured in the laboratory usually do not a
31、ccurately reflectlarge-scale in situ properties because the latter are stronglyinfluenced by joints, faults, inhomogeneity, weakness planes,and other factors. Therefore, laboratory values for intactspecimens must be employed with proper judgment in engi-neering applications.NOTE 2The quality of the
32、result produced by this standard is2For 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.3The last approved version
33、 of this historical standard is referenced onwww.astm.org.4Assembly and detail drawings of an apparatus that meets these requirementsand which is designed to accommodate 54-mm diameter specimens and operate ata confining fluid pressure of 68.9 MPa are available from ASTM InternationalHeadquarters. O
34、rder Adjunct No. ADJD7012. Original adjunct produced in 1982.D7012 1412dependent on the competence of the personnel performing it, and thesuitability of the equipment and facilities used. Agencies that meet thecriteria of Practice D3740 are generally considered capable of competentand objective test
35、ing. Users of this standard are cautioned that compliancewith Practice D3740 does not in itself ensure reliable results. Reliableresults depend on many factors; Practice D3740 provides a means forevaluating some of those factors.6. Apparatus6.1 Compression Apparatus:6.1.1 Methods A to D:6.1.1.1 Load
36、ing DeviceThe loading device shall be ofsufficient capacity to apply load at a rate conforming to therequirements specified in 9.4.1. It shall be verified at suitabletime intervals in accordance with the procedures given inPractices E4 and comply with the requirements prescribed inthe method. The lo
37、ading device may be equipped with adisplacement transducer that can be used to advance theloading ram at a specified rate.NOTE 3For Methods A and B, if the load-measuring device is locatedoutside the confining compression apparatus, calibrations to determine theseal friction need to be made to make
38、sure the loads measured meet theaccuracy specified in Practices E4.6.2 Confining System:46.2.1 Methods A and B:6.2.1.1 Confining Apparatus5The confining pressure ap-paratus shall consist of a chamber in which the test specimenmay be subjected to a constant lateral fluid pressure and therequired axia
39、l load. The apparatus shall have safety valves,suitable entry ports for filling the chamber, and associatedhoses, gages, and valves as needed.6.2.1.2 Flexible MembraneThis membrane encloses therock specimen and extends over the platens to prevent penetra-tion by the confining fluid. A sleeve of natu
40、ral or syntheticrubber or plastic is satisfactory for room temperature tests;however, metal or high-temperature rubber (viton) jackets areusually necessary for elevated temperature tests. The mem-brane shall be inert relative to the confining fluid and shallcover small pores in the specimen without
41、rupturing whenconfining pressure is applied. Plastic or silicone rubber coat-ings may be applied directly to the specimen provided thesematerials do not penetrate and strengthen or weaken thespecimen. Care must be taken to form an effective seal wherethe platen and specimen meet. Membranes formed by
42、 coatingsshall be subject to the same performance requirements aselastic sleeve membranes.6.2.1.3 Pressure-Maintaining DeviceA hydraulic pump,pressure intensifier, or other system having sufficient capacityto maintain the desired lateral pressure to within 61%throughout the test. The confining press
43、ure shall be measuredwith a hydraulic pressure gauge or electronic transducer havingan accuracy of at least 61 % of the confining pressure,including errors due to readout equipment, and a resolution ofat least 0.5 % of the confining pressure.6.2.1.4 Confining-Pressure FluidsHydraulic fluids com-pati
44、ble with the pressure-maintaining device and flexiblemembranes shall be used. For tests using Option A, the fluidmust remain stable at the temperature and pressure levelsdesignated for the test.6.2.2 Option A:6.2.2.1 Temperature EnclosureThe temperature enclosureshall be either an internal system th
45、at fits inside the loadingapparatus or the confining pressure apparatus, an externalsystem enclosing the entire confining pressure apparatus, or anexternal system encompassing the complete test apparatus. Forhigh or low temperatures, a system of heaters or coolers,respectively, insulation, and tempe
46、rature-measuring devicesare normally necessary to maintain the specified temperature.Temperature shall be measured at three locations, with onesensor near the top, one at mid-height, and one near the bottomof the specimen. The “average” specimen temperature, basedon the mid-height sensor, shall be m
47、aintained to within 61Cof the specified test temperature. The maximum temperaturedifference between the mid-height sensor and either end sensorshall not exceed 3C.NOTE 4An alternative to measuring the temperature at three locationsalong the specimen during the test is to determine the temperaturedis
48、tribution in a specimen that has temperature sensors located in drillholes at a minimum of six positions: along both the centerline andspecimen periphery at mid-height and each end of the specimen. Thespecimen may originate from the same batch as the test specimens andconform to the same dimensional
49、 tolerances and to the same degree ofintactness. The temperature controller set point may be adjusted to obtainsteady-state temperatures in the specimen that meet the temperaturerequirements at each test temperature. The centerline temperature atmid-height may be within 61C of the specified test temperature and allother specimen temperatures may not deviate from this temperature bymore than 3C. The relationship between controller set point andspecimen temperature can be used to determine the specimen temperatureduring testing provided that the output
