ASTM D4436-08
(Test Method)Standard Test Method for Rock Bolt Long-Term Load Retention Test
Standard Test Method for Rock Bolt Long-Term Load Retention Test
SIGNIFICANCE AND USE
Rock bolts are used for support in a variety of mining and civil engineering situations. After a bolt is installed, the load generally decreases over time due to deterioration of the borehole wall, creep, and other factors. This process may be arrested by fully encapsulating the bolt shortly after installation. This is generally done by pumping the bolt hole full of cement grout, though synthetic resins may also be used. The rate of load loss determines the interval during which the bolt must be encapsulated during construction.
The local characteristics of the rock, such as roughness of the borehole and induced fractures, are significant factors in the load loss characteristics of the bolt. To obtain realistic values, the test holes should be drilled using the same methods as those used for the construction boreholes.
In establishing a testing program, the following factors should be considered:
Load retention tests should be conducted in all rock types where construction bolts will be installed. If the rock is anisotropic, for example, bedded or schistose, the tests should be conducted in the same orientations relative to the anisotropy as the construction bolts will be installed.
In each rock type, at each orientation, and for each anchor system, a sufficient number of tests should be conducted to determine the average and minimum long-term capacities within a fixed uncertainty band at the 95 % confidence level. The allowable uncertainty band depends on the project and involves such factors as rock quality, expected project lifetime, and importance of the areas to be bolted. The uncertainty band determination will require considerable engineering judgment. As a rough guideline, at least six long-term tests for a single set of variables have been found necessary to satisfy the statistical requirements.
The design load and installation load on the rock bolt system should be predetermined. The installation load is less than the anchor capacity, as determin...
SCOPE
1.1 The objective of this test method is to determine the time over which rock bolt tension decreases from the installed value to a designated minimum value.
1.2 This test method is applicable to any anchor system which is not fully encapsulated immediately upon installation, including mechanical, cement grout, resin (epoxy, polyester, and the like) or other similar systems.
1.3 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.
1.4 All observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice D 6026.
1.4.1 The method used to specify how data are collected, calculated, or recorded in this standard is not directly related to the accuracy to which the data can be applied in design or other uses, or both. How one applies the results obtained using this standard is beyond its scope.
1.5 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: D4436 − 08
StandardTest Method for
1
Rock Bolt Long-Term Load Retention Test
This standard is issued under the fixed designation D4436; 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. Scope* D6026 Practice for Using Significant Digits in Geotechnical
Data
1.1 The objective of this test method is to determine the
D6167 Guide for Conducting Borehole Geophysical Log-
time over which rock bolt tension decreases from the installed
ging: Mechanical Caliper
value to a designated minimum value.
1.2 This test method is applicable to any anchor system
3. Terminology
which is not fully encapsulated immediately upon installation,
3.1 See Terminology D653 for general definitions.
including mechanical, cement grout, resin (epoxy, polyester,
and the like) or other similar systems.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 load—the total axial force on the rock bolt.
1.3 The values stated in inch-pound units are to be regarded
as standard. The values given in parentheses are mathematical 3.2.2 design load—the load specified for the rock bolt
during the life of the project.
conversions to SI units that are provided for information only
and are not considered standard.
3.2.3 installation load—the load on the bolt immediately
after installation.
1.4 All observed and calculated values shall conform to the
guidelines for significant digits and rounding established in
3.2.4 stand time—the time required for the bolt load to
Practice D6026.
decrease from the installation load to the design load.
1.4.1 The method used to specify how data are collected,
calculated, or recorded in this standard is not directly related to
4. Summary of Test Method
theaccuracytowhichthedatacanbeappliedindesignorother
4.1 A rock bolt is installed in the same manner and in the
uses, or both. How one applies the results obtained using this
same material as its intended support use. The load on the bolt
standard is beyond its scope.
is monitored over a period of time, usually several weeks.
1.5 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
5. Significance and Use
responsibility of the user of this standard to establish appro-
5.1 Rock bolts are used for support in a variety of mining
priate safety and health practices and determine the applica-
3
and civil engineering situations. After a bolt is installed, the
bility of regulatory limitations prior to use.
load generally decreases over time due to deterioration of the
borehole wall, creep, and other factors. This process may be
2. Referenced Documents
arrested by fully encapsulating the bolt shortly after installa-
2
2.1 ASTM Standards:
tion. This is generally done by pumping the bolt hole full of
D653 Terminology Relating to Soil, Rock, and Contained
cement grout, though synthetic resins may also be used. The
Fluids
rate of load loss determines the interval during which the bolt
D3740 Practice for Minimum Requirements for Agencies
must be encapsulated during construction.
Engaged in Testing and/or Inspection of Soil and Rock as
5.2 The local characteristics of the rock, such as roughness
Used in Engineering Design and Construction
of the borehole and induced fractures, are significant factors in
D4435 Test Method for Rock Bolt Anchor Pull Test
the load loss characteristics of the bolt. To obtain realistic
values, the test holes should be drilled using the same methods
1
ThistestmethodisunderthejurisdictionofASTMCommitteeD18onSoiland
as those used for the construction boreholes.
Rock and is the direct responsibility of Subcommittee D18.12 on Rock Mechanics.
Current edition approved July 1, 2008. Published July 2008. Originally approved
in 1984. Last previous edition approved in 2004 as D4436 – 04. DOI: 10.1520/
D4436-08.
2 3
For referenced ASTM standards, visit the ASTM website, www.astm.org, or For additional information see, “Suggested Method for Monitoring Rock Bolt
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Tension Using Load Cells,” Suggested Methods for Rock Bolt Testing, International
Standards volume information, refer to the standard’s Document Summary page on Society for Rock Mechanics Commission on Standardization of Laboratory and
the ASTM website. Field Tests, 1974.
*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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D4436 − 08
5.3 In establishing a testing program, the followi
...
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.
Designation:D4436–04 Designation: D 4436 – 08
Standard Test Method for
1
Rock Bolt Long-Term Load Retention Test
This standard is issued under the fixed designation D 4436; 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. Scope*
1.1 The objective of this test method is to determine the time over which rock bolt tension decreases from the installed value
to a designated minimum value.
1.2 Thistestmethodisapplicabletoanyanchorsystemwhichisnotfullyencapsulatedimmediatelyuponinstallation,including
mechanical, cement grout, resin (epoxy, polyester, and the like) or other similar systems.
1.3The values stated in inch-pound units are to be regarded as the standard.
1.4All observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice
D6026
1.3 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical
conversions to SI units that are provided for information only and are not considered standard.
1.4 All observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice
D 6026.
1.4.1 The method used to specify how data are collected, calculated, or recorded in this standard is not directly related to the
accuracy to which the data can be applied in design or other uses, or both. How one applies the results obtained using this standard
is beyond its scope.
1.5 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.
2. Referenced Documents
2
2.1 ASTM Standards:
D 653 Terminology Relating to Soil, Rock, and Contained Fluids
D 3740 Practice for Minimum Requirements forAgencies Engaged in the Testing and/or Inspection of Soil and Rock as Used
in Engineering Design and Construction
D 4435 Test Method for Rock Bolt Anchor Pull Test
D 6026 Practice for Using Significant Digits in Geotechnical Data
D6167Guide 6167 Guide for Conducting Borehole Geophysical Logging: Mechanical Caliper
3. Terminology
3.1See Terminology D653
3.1 See Terminology D 653 for general definitions.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 load—the total axial force on the rock bolt.
3.2.2 design load—the load specified for the rock bolt during the life of the project.
3.2.3 installation load—the load on the bolt immediately after installation.
3.2.4 stand time—the time required for the bolt load to decrease from the installation load to the design load.
4. Summary of Test Method
4.1 A rock bolt is installed in the same manner and in the same material as its intended support use. The load on the bolt is
monitored over a period of time, usually several weeks.
1
This test method is 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 July 1, 2004.2008. Published July 2004.2008. Originally approved in 1984. Last previous edition approved in 19982004 as
D4436–84(1998).D 4436 – 04.
2
For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
*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
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D4436–08
5. Significance and Use
3
5.1 Rock bolts are used for support in a variety of mining and civil engineering situations. After a bolt is installed, the load
generally decreases over time due to deterioration of the borehole wall, creep, and other factors. This process may be arrested by
fully encapsulating the bolt shortly after installation. This is generally done by pumping the bolt hole full of cement grout, though
synthetic resins may also be used. The rate of load loss determines the interval during which the bolt must be encapsulated during
construction.
5.2 The local characteristics of the rock
...
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