ASTM D7012-04
(Test Method)Standard Test Method for Compressive Strength and Elastic Moduli of Intact Rock Core Specimens under Varying States of Stress and Temperatures
Standard Test Method for Compressive Strength and Elastic Moduli of Intact Rock Core Specimens under Varying States of Stress and Temperatures
SCOPE
1.1 This test method covers the determination of the strength of intact rock core specimens in uniaxial compression and confined compression. The tests provide data in determining the strength of rock, namely: the uniaxial strength, shear strengths at varying pressures and varying temperatures, angle of internal friction, (angle of shearing resistance), and cohesion intercept. The test method specifies the apparatus, instrumentation, and procedures for determining the stress-axial strain and the stress-lateral strain curves, as well as Young's modulus, E, and Poisson's ratio, . It should be observed that this method makes no provision for pore pressure measurements and specimens are undrained (platens are not vented). Thus the strength values determined are in terms of total stress, that is, are not corrected for pore pressures. This test method does not include the procedures necessary to obtain a stress-strain curve beyond the ultimate strength.
1.1.1 This standard replaces and combines the following Standard Test Methods for: D 2664 Triaxial Compressive Strength of Undrained Rock Core Specimens Without Pore Pressure Measurements; D 5407 Elastic Moduli of Undrained Rock Core Specimens in Triaxial Compression Without Pore Pressure Measurements; D 2938 Unconfined Compressive Strength of Intact Rock Core Specimens; and D 3148 Elastic Moduli of Intact Rock Core Specimens in Uniaxial Compression.
1.1.2 The original four standards are now referred to as Methods in this standard as follows: Method A - Triaxial Compressive Strength of Undrained Rock Core Specimens Without Pore Pressure Measurements; Method B - Elastic Moduli of Undrained Rock Core Specimens in Triaxial Compression Without Pore Pressure Measurements; Method C - Unconfined Compressive Strength of Intact Rock Core Specimens; Method D - Elastic Moduli of Intact Rock Core Specimens in Uniaxial Compression; and Option A - Elevated Temperatures.
1.1.3 The original four standards are now referred to as Methods in this standard as follows: Method A (D2664) Triaxial Compressive Strength of Undarined Rock Core Specimens Without Pore Pressure Measurements; Method B (D5407) Elastic Moduli of Undrained Rock Core Specimens in Triaxial Compression Without Pore Pressure Measurements, Method C (D2938 Unconfined Compressive Strength of Intact Rock Core Specimens; Method D (d3148) Elastic Moduli of Intact Rock Core Specimerns in Uniaxial Compression; and Option A Elevated Temperatures.
1.2 For an isotropic material, the relation between the shear and bulk moduli and Young's modulus and Poisson's ratio are:Equation 1 - G = E/21 + Equation 2 - K = E/31 2where:Gshear modulus,Kbulk modulus, EYoung's modulus, and Poisson's ratio.
1.2.1 The engineering applicability of these equations decreases with increasing anisotropy of the rock. It is desirable to conduct tests in the plane of foliation, cleavage or bedding and at right angles to it to determine the degree of anisotropy. It is noted that equations developed for isotropic materials may give only approximate calculated results if the difference in elastic moduli in two orthogonal directions is greater than 10 % for a given stress level.Note 1
Elastic moduli measured by sonic methods (Test Method D 2845) may often be employed as preliminary measures of anisotropy.
1.3 This test method given for determining the elastic constants does not apply to rocks that undergo significant inelastic strains during the test, such as potash and salt. The elastic moduli for such rocks should be determined from unload-reload cycles, that are not covered by this test method.
1.4 The values stated in SI units are to be regarded as the standard.
This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Designation: D 7012 – 04
Standard Test Method for
Compressive Strength and Elastic Moduli of Intact Rock
Core Specimens under Varying States of Stress and
1
Temperatures
This standard is issued under the fixed designation D 7012; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope mens; Method D — Elastic Moduli of Intact Rock Core
SpecimensinUniaxialCompression;andOptionA—Elevated
1.1 This test method covers the determination of the
Temperatures.
strength of intact rock core specimens in uniaxial compression
1.1.3 The original four standards are now referred to as
and confined compression. The tests provide data in determin-
Methods in this standard as follows: Method A (D2664)
ing the strength of rock, namely: the uniaxial strength, shear
Triaxial Compressive Strength of Undarined Rock Core Speci-
strengths at varying pressures and varying temperatures, angle
mens Without Pore Pressure Measurements; Method B
ofinternalfriction,(angleofshearingresistance),andcohesion
(D5407) Elastic Moduli of Undrained Rock Core Specimens in
intercept. The test method specifies the apparatus, instrumen-
Triaxial Compression Without Pore Pressure Measurements,
tation, and procedures for determining the stress-axial strain
Method C (D2938 Unconfined Compressive Strength of Intact
andthestress-lateralstraincurves,aswellasYoung’smodulus,
Rock Core Specimens; Method D (d3148) Elastic Moduli of
E,andPoisson’sratio, y.Itshouldbeobservedthatthismethod
Intact Rock Core Specimerns in Uniaxial Compression; and
makes no provision for pore pressure measurements and
Option A Elevated Temperatures.
specimens are undrained (platens are not vented). Thus the
1.2 For an isotropic material, the relation between the shear
strength values determined are in terms of total stress, that is,
and bulk moduli andYoung’s modulus and Poisson’s ratio are:
are not corrected for pore pressures. This test method does not
include the procedures necessary to obtain a stress-strain curve E
G 5 (1)
2~11y!
beyond the ultimate strength.
1.1.1 This standard replaces and combines the following
E
K 5 (2)
Standard Test Methods for: D 2664 Triaxial Compressive
3~1 2 2y!
Strength of Undrained Rock Core Specimens Without Pore
where:
Pressure Measurements; D 5407 Elastic Moduli of Undrained
G = shear modulus,
Rock Core Specimens in Triaxial Compression Without Pore
K = bulk modulus,
Pressure Measurements; D 2938 Unconfined Compressive
E = Young’s modulus, and
Strength of Intact Rock Core Specimens; and D 3148 Elastic
y = Poisson’s ratio.
Moduli of Intact Rock Core Specimens in Uniaxial Compres-
1.2.1 The engineering applicability of these equations de-
sion.
creases with increasing anisotropy of the rock. It is desirable to
1.1.2 The original four standards are now referred to as
conduct tests in the plane of foliation, cleavage or bedding and
Methods in this standard as follows: Method A — Triaxial
at right angles to it to determine the degree of anisotropy. It is
Compressive Strength of Undrained Rock Core Specimens
notedthatequationsdevelopedforisotropicmaterialsmaygive
Without Pore Pressure Measurements; Method B — Elastic
only approximate calculated results if the difference in elastic
Moduli of Undrained Rock Core Specimens in Triaxial Com-
moduli in two orthogonal directions is greater than 10 % for a
pression Without Pore Pressure Measurements; Method C —
given stress level.
Unconfined Compressive Strength of Intact Rock Core Speci-
NOTE 1—Elastic moduli measured by sonic methods (Test Method
D 2845) may often be employed as preliminary measures of anisotropy.
1.3 This test method given for determining the elastic
1
ThistestmethodisunderthejurisdictionofASTMCommitteeD18onSoiland
constants does not apply to rocks that undergo significant
Rock and is the direct responsibility of Subcommittee D18.12 on Rock Mechanics.
Current edition approved Feb. 1, 2004. Published February 2004. inelastic strains during the test, such as potash and salt. The
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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D7012–04
elastic moduli for such rocks should be determined from underground rock masses exist. The elastic constants are used
unload-reload cycles, that are not covered by this test method. to calculate the stress and deformation in rock structures.
1.4 The values stated in SI units are to be regarded as the 4.3 The deformation and strength properties of rock cores
standard. measured in the laboratory usually do not accurately reflect
1.5 This
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