ASTM D7012-14e1
(Test Method)Standard Test Methods for Compressive Strength and Elastic Moduli of Intact Rock Core Specimens under Varying States of Stress and Temperatures
Standard Test Methods for Compressive Strength and Elastic Moduli of Intact Rock Core Specimens under Varying States of Stress and Temperatures
SIGNIFICANCE AND USE
5.1 The parameters obtained from Methods A and B are in terms of undrained total stress. However, there are some cases where either the rock type or the loading condition of the problem under consideration will require the effective stress or drained parameters be determined.
5.2 Method C, uniaxial compressive strength of rock is used in many design formulas and is sometimes used as an index property to select the appropriate excavation technique. Deformation and strength of rock are known to be functions of confining pressure. Method A, triaxial compression test, is commonly used to simulate the stress conditions under which most underground rock masses exist. The elastic constants (Methods B and D) are used to calculate the stress and deformation in rock structures.
5.3 The deformation and strength properties of rock cores measured in the laboratory usually do not accurately reflect large-scale in situ properties because the latter are strongly influenced by joints, faults, inhomogeneity, weakness planes, and other factors. Therefore, laboratory values for intact specimens must be employed with proper judgment in engineering applications.
Note 2: The quality of the result produced by this standard is dependent on the competence of the personnel performing it, and the suitability of the equipment and facilities used. Agencies that meet the criteria of Practice D3740 are generally considered capable of competent and objective testing. Users of this standard are cautioned that compliance with Practice D3740 does not in itself ensure reliable results. Reliable results depend on many factors; Practice D3740 provides a means for evaluating some of those factors.
SCOPE
1.1 These four test methods cover the determination of the strength of intact rock core specimens in uniaxial and triaxial compression. Methods A and B determine the triaxial compressive strength at different pressures and Methods C and D determine the unconfined, uniaxial strength.
1.2 Methods A and B can be used to determine the angle of internal friction, angle of shearing resistance, and cohesion intercept.
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 as Young's modulus, E, and Poisson's ratio, υ. These methods make 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 and are not corrected for pore pressures. These test methods do not include the procedures necessary to obtain a stress-strain curve beyond the ultimate strength.
1.4 Option A allows for testing at different temperatures and can be applied to any of the test methods, if requested.
1.5 This standard replaces and combines the following Standard Test Methods: D2664 Triaxial Compressive Strength of Undrained Rock Core Specimens Without Pore Pressure Measurements; D5407 Elastic Moduli of Undrained Rock Core Specimens in Triaxial Compression Without Pore Pressure Measurements; D2938 Unconfined Compressive Strength of Intact Rock Core Specimens; and D3148 Elastic Moduli of Intact Rock Core Specimens in Uniaxial Compression. The original four standards are now referred to as Methods in this standard.
1.5.1 Method A: Triaxial Compressive Strength of Undrained Rock Core Specimens Without Pore Pressure Measurements.
1.5.1.1 Method A is used for obtaining strength determinations. Strain is not typically measured; therefore a stress-strain curve is not produced.
1.5.2 Method B: Elastic Moduli of Undrained Rock Core Specimens in Triaxial Compression Without Pore Pressure Measurements.
1.5.3 Method C: Uniaxial Compressive Strength of Intact Rock Core Specimens.
1.5.3.1 Method C is used for obtaining strength determinations. Strain is not typically measured; therefore a stress-strain curve is not produced.
1.5.4 Method D:...
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´1
Designation: D7012 − 14
Standard Test Methods 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 D7012; 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 (´) indicates an editorial change since the last revision or reapproval.
1
ε NOTE—Editorially corrected legend for Eq 3 in August 2017.
1. Scope 1.5.1 Method A: Triaxial Compressive Strength of Und-
rained Rock Core Specimens Without Pore Pressure Measure-
1.1 These four test methods cover the determination of the
ments.
strength of intact rock core specimens in uniaxial and triaxial
1.5.1.1 Method A is used for obtaining strength determina-
compression. Methods A and B determine the triaxial compres-
tions. Strain is not typically measured; therefore a stress-strain
sive strength at different pressures and Methods C and D
curve is not produced.
determine the unconfined, uniaxial strength.
1.5.2 Method B: Elastic Moduli of Undrained Rock Core
1.2 Methods A and B can be used to determine the angle of
Specimens in Triaxial Compression Without Pore Pressure
internal friction, angle of shearing resistance, and cohesion
Measurements.
intercept.
1.5.3 Method C: Uniaxial Compressive Strength of Intact
1.3 Methods B and D specify the apparatus,
Rock Core Specimens.
instrumentation, and procedures for determining the stress-
1.5.3.1 Method C is used for obtaining strength determina-
axial strain and the stress-lateral strain curves, as well as
Young’s modulus, E, and Poisson’s ratio, υ. These methods tions. Strain is not typically measured; therefore a stress-strain
curve is not produced.
make no provision for pore pressure measurements and speci-
mens are undrained (platens are not vented). Thus, the strength
1.5.4 Method D: Elastic Moduli of Intact Rock Core Speci-
values determined are in terms of total stress and are not
mens in Uniaxial Compression.
corrected for pore pressures. These test methods do not include
1.5.5 Option A: Temperature Variation—Applies to any of
the procedures necessary to obtain a stress-strain curve beyond
the methods and allows for testing at temperatures above or
the ultimate strength.
below room temperature.
1.4 Option A allows for testing at different temperatures and
1.6 For an isotropic material in Test Methods B and D, the
can be applied to any of the test methods, if requested.
relation between the shear and bulk moduli and Young’s
1.5 This standard replaces and combines the following
modulus and Poisson’s ratio are:
Standard Test Methods: D2664 Triaxial Compressive Strength
E
of Undrained Rock Core Specimens Without Pore Pressure
G 5 (1)
2~11υ!
Measurements; D5407 Elastic Moduli of Undrained Rock Core
Specimens in Triaxial Compression Without Pore Pressure E
K 5 (2)
3 1 2 2υ
Measurements; D2938 Unconfined Compressive Strength of ~ !
Intact Rock Core Specimens; and D3148 Elastic Moduli of
where:
Intact Rock Core Specimens in Uniaxial Compression. The
G = shear modulus,
original four standards are now referred to as Methods in this
K = bulk modulus,
standard.
E = Young’s modulus, and
υ = Poisson’s ratio.
1
1.6.1 The engineering applicability of these equations de-
These test methods are under the jurisdiction of ASTM Committee D18 on Soil
and Rock and is the direct responsibility of Subcommittee D18.12 on Rock
creases with increasing anisotropy of the rock. It is desirable to
Mechanics.
conduct tests in the plane of foliation, cleavage or bedding and
Current edition approved May 1, 2014. Published June 2014. Originally
at right angles to it to determine the degree of anisotropy. It is
approved in 2004. Last previous edition approved in 2013 as D7012 – 13. DOI:
10.1520/D7012-14E01. noted that equations developed for isotropic materials may give
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
---------------------- Page: 1 ----------------------
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D7012 − 14
only approximate calculated results if the difference in elastic Used in Engineering Design and Construction
moduli in two orthogonal directions is greater than 10 % for a D4543 Practices for Preparing Rock Core as Cylindrical Test
given stress level. Specimens and Verifying Conformance to Dimensional
3
and Shape Tolerances (Withdrawn 2017)
NOTE 1—Elastic moduli measured by sonic methods (Test Method
D6026 Practice for Using Significant Digits in Geotechnical
D2845) may often be employed as a preliminary measure of anisotropy.
Data
1.7 Test Methods B and D for determining the e
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
´1
Designation: D7012 − 14 D7012 − 14
Standard Test Methods 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 D7012; 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 (´) indicates an editorial change since the last revision or reapproval.
1
ε NOTE—Editorially corrected legend for Eq 3 in August 2017.
1. Scope
1.1 These four test methods cover the determination of the strength of intact rock core specimens in uniaxial and triaxial
compression. Methods A and B determine the triaxial compressive strength at different pressures and Methods C and D determine
the unconfined, uniaxial strength.
1.2 Methods A and B can be used to determine the angle of internal friction, angle of shearing resistance, and cohesion intercept.
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 as Young’s modulus, E, and Poisson’s ratio, υ. These methods make 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 and are not corrected for pore pressures. These test methods do not include the procedures necessary to obtain a
stress-strain curve beyond the ultimate strength.
1.4 Option A allows for testing at different temperatures and can be applied to any of the test methods, if requested.
1.5 This standard replaces and combines the following Standard Test Methods: D2664 Triaxial Compressive Strength of
Undrained Rock Core Specimens Without Pore Pressure Measurements; D5407 Elastic Moduli of Undrained Rock Core
Specimens in Triaxial Compression Without Pore Pressure Measurements; D2938 Unconfined Compressive Strength of Intact
Rock Core Specimens; and D3148 Elastic Moduli of Intact Rock Core Specimens in Uniaxial Compression. The original four
standards are now referred to as Methods in this standard.
1.5.1 Method A: Triaxial Compressive Strength of Undrained Rock Core Specimens Without Pore Pressure Measurements.
1.5.1.1 Method A is used for obtaining strength determinations. Strain is not typically measured; therefore a stress-strain curve
is not produced.
1.5.2 Method B: Elastic Moduli of Undrained Rock Core Specimens in Triaxial Compression Without Pore Pressure
Measurements.
1.5.3 Method C: Uniaxial Compressive Strength of Intact Rock Core Specimens.
1.5.3.1 Method C is used for obtaining strength determinations. Strain is not typically measured; therefore a stress-strain curve
is not produced.
1.5.4 Method D: Elastic Moduli of Intact Rock Core Specimens in Uniaxial Compression.
1.5.5 Option A: Temperature Variation—Applies to any of the methods and allows for testing at temperatures above or below
room temperature.
1.6 For an isotropic material in Test Methods B and D, the relation between the shear and bulk moduli and Young’s modulus
and Poisson’s ratio are:
E
G 5 (1)
2 11υ
~ !
E
K 5 (2)
3 12 2υ
~ !
1
These test methods are under the jurisdiction of ASTM Committee D18 on Soil and Rock and is the direct responsibility of Subcommittee D18.12 on Rock Mechanics.
Current edition approved May 1, 2014. Published June 2014. Originally approved in 2004. Last previous edition approved in 2013 as D7012 – 13. DOI:
10.1520/D7012-14.10.1520/D7012-14E01.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
---------------------- Page: 1 ----------------------
´1
D7012 − 14
where:
G = shear modulus,
K = bulk modulus,
E = Young’s modulus, and
υ = Poisson’s ratio.
1.6.1 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 D2845) may often be employed as a preliminary measure of anisotropy.
1.7 Test Methods
...
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