Standard Test Method for Determining Deformability and Strength of Weak Rock by an In Situ Uniaxial Compressive Test

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1.1 This test method covers the measurement of the deformability and strength of large in situ specimens of weak rock by a uniaxial - compressive test. The test results take into account the effect of both intact material behavior and the behavior of discontinuities contained within the specimen block.
1.2 The values stated in SI units are to be regarded as the standard.
1.3 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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Historical
Publication Date
09-Nov-2001
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Drafting Committee
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ASTM D4555-01 - Standard Test Method for Determining Deformability and Strength of Weak Rock by an In Situ Uniaxial Compressive Test
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:D4555–01
Standard Test Method for
Determining Deformability and Strength of Weak Rock by an
1
In Situ Uniaxial Compressive Test
This standard is issued under the fixed designation D4555; 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 * results of laboratory tests on small specimens, in situ tests on
large specimens are necessary. Such tests also have the
1.1 Thistestmethodcoversthemeasurementofthedeform-
advantage that the rock specimen is tested under similar
ability and strength of large in situ specimens of weak rock by
environmental conditions as prevailing for the rock mass.
a uniaxial - compressive test.The test results take into account
4.2 Sincethestrengthofrockisdependentonthesizeofthe
the effect of both intact material behavior and the behavior of
test specimen, it is necessary to test several specimens (labo-
discontinuities contained within the specimen block.
ratoryorfield,orboth)ofprogressivelyincreasingsizeuntilan
1.2 The values stated in SI units are to be regarded as the
asymptotically constant strength value is found. This value is
standard.
3,4
taken to represent the strength of the rock mass.
1.3 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
NOTE 1—Notwithstanding the statements on precision and bias con-
responsibility of the user of this standard to establish appro- tained in this test method; the precision of this test method is dependent
onthecompetenceofthepersonnelperformingit,andthesuitabilityofthe
priate safety and health practices and determine the applica-
equipment and facilities used. Agencies that meet the criteria of Practice
bility of regulatory limitations prior to use.
D3740 are generally considered capable of competent and objective
testing. Users of this test method are cautioned that compliance with
2. Referenced Documents
Practice D3740 does not in itself assure reliable testing. Reliable testing
2.1 ASTM Standards:
dependsonmanyfactors.PracticeD3740providesameansofevaluating
D3740 Practice for Minimum Requirements for Agencies
some of those factors.
Engaged in theTesting and/or Inspection of Soil and Rock
2
5. Apparatus
as Used In Engineering Design and Construction
5.1 Preparation Equipment—Equipment is needed for cut-
3. Terminology
ting specimen blocks from existing underground exposed
3.1 Definitions of Terms Specific to This Standard:
faces,forexample,acoalcuttingmachine,pneumaticchisel,or
3.1.1 rock quality designation, RQD—a method for quanti-
other hand tools. No explosives are permitted.
tativelydescribingthenatureofarockmassfromcoreborings.
5.2 Loading System:
RQD is obtained by measuring the total length of all unweath-
5.2.1 Hydraulic Jacks or Flatjacks—This equipment is
ered pieces of core greater than or equal to 100 mm and
required to apply a uniformly distributed load to the complete
dividing the total by the length of the particular core run. This
upper face of the specimen. The loading system shall be of
quantityisexpressedasapercentandisusedtoclassifyinsitu
sufficient capacity and travel to load the system to failure.
rock.
Multiple hydraulic jacks fed by a common manifold should be
3.1.2 weak rock—rock containing numerous weathered
avoided.
jointsspaced30to500mm,withgougefilling/wasterockwith
5.2.2 Hydraulic Pumping System—Thissystemisneededto
fines. Weak rock has both rock and soil properties depending
supply oil at the required pressure to the jacks, the pressure
on condition of use. The compressive strength is less than 35
being controlled to give a constant rate of displacement or
MPa and the RQD is less than 50%.
strain, rather than a constant rate of stress increase.
NOTE 2—Experience has shown that deformation-controlled loading is
4. Significance and Use
preferable to stress-controlled loading because it results in a more stable,
4.1 Since there is no reliable method of predicting the
and thus safer, test. This result is a consequence of the strain softening
overall strength and deformation data of a rock mass from the
nature of most rock or rock-like materials. A single stress level may
1
This test method is under the jurisdiction of Committee D18 on Soil and Rock
3
and is the direct responsibility of Subcommittee D18.12 on Rock Mechanics. Bieniawski,Z.T.,andVanHeerdan,W.L.,“TheSignificanceofLarge-ScaleIn
Current edition approved Nov. 10, 2001. Published February 2002. Originally SituTests,” International Journal of Rock Mechanics Mining Sciences,Vol1,1975.
4
published as D4555–85. Last previous edition D4555–90(1995). Heuze, F. E., “Scale Effects in
...

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