ASTM D4623-05
(Test Method)Standard Test Method for Determination of In Situ Stress in Rock Mass by Overcoring Method-USBM Borehole Deformation Gage
Standard Test Method for Determination of In Situ Stress in Rock Mass by Overcoring Method-USBM Borehole Deformation Gage
SCOPE
1.1 This test method covers the determination of the ambient local stresses in a rock mass and the equipment required to perform in situ stress tests using a three-component borehole deformation gage (BDG). The test procedure and method of data reduction are described, including the theoretical basis and assumptions involved in the calculations. A section is included on troubleshooting equipment malfunctions. Note 1The gage used in this test method is commonly referred to as a USBM gage (U.S. Bureau of Mines three-component borehole deformation gage).
1.2 The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are provided for information only.
This standard does not purport to address all of the safety problems, 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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Standards Content (Sample)
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Designation:D4623–05
Standard Test Method for
Determination of In Situ Stress in Rock Mass by Overcoring
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Method—USBM Borehole Deformation Gage
This standard is issued under the fixed designation D4623; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope* D4395 Test Method for Determining the In Situ Modulus
of Deformation of Rock Mass Using the Flexible Plate
1.1 This test method covers the determination of the ambi-
Loading Method
ent local stresses in a rock mass and the equipment required to
D6026 Practice for Using Significant Digits in Geotechni-
perform in situ stress tests using a three-component borehole
cal Data
deformation gage (BDG). The test procedure and method of
D7012 Test Method for Compressive Strength and Elastic
datareductionaredescribed,includingthetheoreticalbasisand
Moduli of Intact Rock Core Specimens under Varying
assumptions involved in the calculations.Asection is included
States of Stress and Temperatures
on troubleshooting equipment malfunctions.
NOTE 1—The gage used in this test method is commonly referred to as 3. Terminology
a USBM gage (U.S. Bureau of Mines three-component borehole defor-
3.1 Definitions: See Terminology D653 for general defini-
2
mation gage).
tions.
1.2 Thevaluesstatedininch-poundunitsaretoberegarded
3.2 Definitions:
as the standard. The values given in parentheses are provided
3.2.1 deformation—displacement change in dimension of
for information only.
the borehole due to changes in stress.
1.3 This standard does not purport to address all of the
3.2.2 in situ stress—the stress levels and orientations exist-
safety problems, if any, associated with its use. It is the
ing in the rock mass before excavation.
responsibility of the user of this standard to establish appro-
4. Summary of Test Method
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use.
4.1 Theovercoretestmeasuresthediametraldeformationof
a small-diameter borehole as it is removed from the surround-
2. Referenced Documents
ing stress field by coaxially coring a larger diameter hole.
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2.1 ASTM Standards:
Deformation is measured across three diameters of the small
D653 Terminology Relating to Soil, Rock, and Contained
hole, spaced 60° apart, using a deformation gage developed by
Fluids
the U.S. Bureau of Mines. With knowledge of the rock
D3740 Practice for Minimum Requirements for Agencies
deformation moduli, the measured borehole deformation can
Engaged in theTesting and/or Inspection of Soil and Rock
berelatedtothechangeinstressinaplaneperpendiculartothe
Used in Engineering Design and Construction
borehole. This change in stress is assumed to be numerically
D4394 Test Method for Determining the In Situ Modulus
equal, although opposite in sense to the stresses existing in the
of Deformation of Rock Mass Using the Rigid Plate
parent rock mass. Deformation measurements from three
Loading Method
nonparallel boreholes, together with rock deformation moduli,
allow calculation of an estimate of the complete three-
dimensional state of stress in the rock mass.
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ThistestmethodisunderthejurisdictionofASTMCommitteeD18onSoiland
5. Significance and Use
Rock and is the direct responsibility of Subcommittee D18.12 on Rock Mechanics.
Current edition approved Nov. 1, 2005. Published November 2005. Originally
5.1 Either virgin stresses or the stresses as influenced by an
approved in 1986. Last previous edition approved in 2002 as D4623–02
excavation may be determined. This test method is written
2
Considerable information presented in this test method was taken from Bureau
assuming testing will be done from an underground opening;
of Mines Information Circular No. 8618, and Hooker, V.E., and Bickel, D.L.,
“Overcoring Equipment and Techniques Used in Rock Stress Determination,” however, the same principles may be applied to testing in a
Denver Mining Research Center, Denver, CO, 1974.
rock outcrop at the surface.
3
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
5.2 Thistestmethodisgenerallyperformedatdepthswithin
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
50 ft (15 m) of the working face because of drilling difficulties
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. at greater depths. Some deeper testing has been done, but
*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.
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