ASTM D4553-02(2006)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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:D4553–02 (Reapproved 2006)
Standard Test Method for
Determining In Situ Creep Characteristics of Rock
This standard is issued under the fixed designation D4553; 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* D4403 Practice for Extensometers Used in Rock
1.1 This test method covers the preparation, equipment, test
3. Terminology
procedure, and data documentation for determining in situ
3.1 Definitions: See Terminology D653 for general defini-
creep characteristics of a rock mass using a rigid plate
tions.
subjected to controlled loading.
3.2 Definitions of Terms Specific to This Standard:
1.2 This test method is designed to be conducted in an
3.2.1 creep—a time-dependent displacement of a plate
underground opening; however, with suitable modifications,
pushed into the surface of the rock by a constant normal load.
this test could be conducted at the surface.
It is not directly related with laboratory creep data because of
1.3 Thetestisusuallyconductedparallelorperpendicularto
the nonuniformity of stress within the rock mass underneath
the anticipated axis of thrust, as dictated by the design load or
the plate.
other orientations, based upon the application.
3.2.2 displacement—movement of the rigid plate, grout
1.4 Flexible plate apparatus can be used if the anticipated
pad, or rock in response to and in the same direction as the
creep displacement is within the tolerance of the travel of the
applied load.
flat jacks.
3.2.3 load—total force acting on the rock face.
1.5 The values stated in inch-pound units are to be regarded
3.2.4 rigid plate—platewithadeflectionoflessthan0.0005
as the standard.
in. (0.0125 mm) from the center to the edge of the plate when
1.6 This standard does not purport to address all of the
maximum load is applied.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
4. Summary of Test Method
priate safety and health practices and determine the applica-
4.1 Areas on two opposing faces of a test opening are
bility of regulatory limitations prior to use. For specific
flattened, smoothed, and made parallel.
precaution statements, see Section 8.
4.2 A grout pad and rigid metal plate are installed against
2. Referenced Documents eachfaceandahydraulicloadingsystemisplacedbetweenthe
2 rigid plates.
2.1 ASTM Standards:
4.3 The two faces are rapidly loaded to the desired creep
D653 Terminology Relating to Soil, Rock, and Contained
load,withoutshock,theloadmaintained,andthedisplacement
Fluids
of the plate measured as a function of time.
D3740 Practice for Minimum Requirements for Agencies
Engaged in theTesting and/or Inspection of Soil and Rock
5. Significance and Use
as Used in Engineering Design and Construction
5.1 Results of this test method are used to predict time-
D4394 Test Method for Determining the In Situ Modulus
dependent deformation characteristics of a rock mass resulting
of Deformation of Rock Mass Using the Rigid Plate
from loading. It is a test that may be required depending on
Loading Method
rock type or anticipated loads, or both.
5.2 This test method may be useful in structural design
analysis where loading is applied over an extensive period.
ThistestmethodisunderthejurisdictionofASTMCommitteeD18onSoiland
5.3 This test method is normally performed at ambient
Rock and is the direct responsibility of Subcommittee D18.12 on Rock Mechanics.
temperature, but equipment can be modified or substituted for
Current edition approved May 1, 2006. Published June 2006. Originally
approved in 1985. Last previous edition approved in 2002 as D4553–02.
operations at other temperatures.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
5.4 Results of this test method may be useful in verifying
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
laboratory creep data and structural mathematical modeling
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. analyses.
*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.
D4553–02 (2006)
5.5 Creep characteristics are determined under a nonuni- 7.3.2 The loading equipment includes a device for applying
form state of stress. the load and the reaction members, usually thick-walled
aluminum or steel pipes, to transmit the load.
5.6 If during a field investigation, time-dependent charac-
7.3.3 Load Maintaining Equipment—Equipment such as a
teristics are detected, then an in situ creep test shall be
servo-control system or air over hydraulic oil is required.
performed.
7.3.4 Bearing Pads—The bearing pads shall have a modu-
NOTE 1—The quality of the result produced by this standard is 6 4
lusofelasticityofatleast4 310 psi(3 310 MPa)(30GPa)
dependent on the competence of the personnel performing it, and the
and shall be capable of conforming to the rock surface and
suitability of the equipment and facilities used. Agencies that meet the
bearing plate. High early strength grout or molten sulfur
criteria of Practice D3740 are generally considered capable of competent
bearing pads are recommended.
and objective testing/sampling/inspection/etc. Users of this standard are
cautioned that compliance with Practice D3740does not in itself assure
7.3.5 Bearing Plates—Thebearingplatesshallapproximate
reliable results. Reliable results depend on many factors; Practice D3740
a rigid die as closely as practical.Abearing plate that has been
provides a means of evaluating some of those factors.
foundsatisfactoryisshowninFig.1.Althoughtheexactdesign
and materials may differ, the stiffness of the bearing plate shall
6. Interferences
be at least the minimum stiffness necessary to produce no
6.1 Acompletely inflexible plate used to load the rock face
measurable deflection of the plate under maximum load.
is difficult to construct. However, if the plate is constructed as
rigid as feasible, the rock face is smoothed, and a thin,
8. Precautions
high-modulus material is used for the pad, the error in the
8.1 All equipment and apparatus shall comply with the
measured displacements will be minimal.
performance specifications in Section 7 and apparatus shall be
6.2 The rock under the loaded area is generally not homo-
verified. If no requirements are stated in Section 7, the
geneous, as assumed in theory. The rock will respond to the
manufacturer’s specifications for the equipment may be appro-
load according to its local deformational characteristics and
priate as a guide to assure acceptable performance. Perfor-
orientation of discontinuities. The use of the average plate
mance verification is generally done by calibrating the equip-
displacement will mitigate this problem. If this creep test is
ment and measurement system (see Fig. 2).
performed immediately after a plate loading test, the results of
8.2 Enforce safety by applicable safety standards. Pressure
the creep test will be different than if it had been performed on
lines must be bled of air to preclude violent failure of the
virgin rock.
pressure system.
7. Apparatus
9. In Situ Conditions
7.1 Surface Preparation Equipment— Test-site preparation
9.1 Areas that are geologically representative of the mass
equipment should include an assortment of excavation tools,
shall be selected. The plates shall be contained in the same
such as drills and chipping hammers. Blasting shall not be
geologic member. The testing program shall be designed so
allowed during final preparation of the test site.
that effects of local geology can be clearly distinguished and
7.2 Instrumentation:
the impact of excavation minimized.
7.2.1 Displacement Measuring Equipment— For displace-
9.2 The size of the bearing plate will be determined by the
ment measurements, dial gages or linear variable differential
local geology, pressures to be applied, and the size of the
transformers (LVDTs) are generally used. A sensitivity of at
opening in which the test is to be performed.These parameters
least 60.0001 in. (0.0025 mm), including the error of the
shall be considered prior to excavation of the opening. Opti-
readout equipment, and an accuracy of at least 0.0005 in.
mumopeningdimensionsareapproximatelysixtimestheplate
(0.0125 mm) are required. Errors in excess of 0.0004 in. (0.01
diameter. Recommended plate diameter is commonly 1 1/2 to
mm)caninvalidatetestresultswhenthemodulusofrockmass
3 1/2 ft (0.5 to 1 m). Other plate sizes may be used depending
6 4
exceeds 5 310 psi (3.5 310 MPa).
upon site specifics.
7.2.2 Load Cell—A load cell is recommended to measure
9.3 The effects of anisotropy shall be investigated by
the load on the bearing plate. An accuracy of 61000 lbf (4.4
appropriately oriented tests; for example, parallel and perpen-
kN) or 65 % of maximum test load, including errors intro-
dicular to the long axes of columns in a basalt flow.
duced by the readout system, and a sensitivity of at least 500
9.4 Tests shall be performed at a site not affected by
lbf (2.2 kN) are reasonable. Long-term stability of the instru-
structural changes resulting from excavations of the opening.
mentation system shall be verified throughout the test.
Thezoneofrockthatcontributestothemeasureddisplacement
7.3 Loading Equipment:
during loading depends on the diameter of the plate and the
applied load. Larger plates and higher loads measure the
7.3.1 Hydraulic Ram or Flat Jacks—This equipment, ca-
pable of applying and maintaining desired pressures to response of rock farther away from the test opening. Thus, if
the rock around the opening is damaged by the excavation
within6 3 %, is usually used to apply the load. A spherical
bearing of suitable capacity shall be coupled to one of the process and the creep properties of the damaged zone are the
primary objective of the test program, small-diameter plate
bearing plates. If a hydraulic ram is used, the load shall be
corrected to account for the effects of ram friction. If flat jacks tests on typically excavated surfaces are adequate.
are used, the jacks shall not be expanded beyond a thickness 9.5 Siteconditionsmaydictatethatsitepreparationandpad
equal to3%ofthe diameter of a metal jack. construction be performed immediately after excavation.
D4553–02 (2006)
FIG. 1 Rigid Bearing Plate for 12 in. Diameter Test
10. Procedure from the excavation. Deeper breaks may be detected by a dull
hollow sound when the rock surface is struck with a hammer;
10.1 Aschematic of an optimum test setup is shown in Fig.
remove such material.
3. A properly located platform (not shown) allows for align-
10.3.4 Smoothness—The prepared rock face shall be as
ment of all test components.
smooth as practicable. In no case shall the deviation from a
10.2 Conduct the test across a “diameter” or chord of the
plane between the highest and lowest points exceed 1 in. (25
openingwiththetwotestsurfacesnearlyparallelandinplanes
mm).
oriented perpendicular to the thrust of the loading assembly.
10.3.5 Cleaning—After the surface has been prepared,
10.3 Surface Preparation:
scrub and rinse it with clean water to remove any loose
10.3.1 Method—Prepare the surface by a method that
particles or dirt caused by the smoothing operation.
causes minimal damage to the finished rock surface. In the
initial preparation of the finished test surface, many short drill 10.4 Bearing Pad Construction—Constructthebearingpad,
with the bearing plate in position, by pouring the pad material
holes may be required to remove unsound rock. Any residual
between the rock surface and the plate. Contain the pad
rock between the drill holes may be removed by burnishing or
material by suitable form work around the edges of the plate.
moving the bit back and forth until a smooth face is achieved.
The only exception to this method is for near vertical tests
Alternatively,inhard,competentrock,controlledblastingwith
wheregroutpadsareused.Inthiscase,thelowerbearingplate
very small charges may be required to remove the unwanted
may be placed directly upon the pad prior to curing. In all
materials. In weaker materials, coarse grinding or cutting
cases,exercisecaretoavoidairpocketsorothercavitieswithin
devices may be used.
the pad. The thickness of the pad shall be no more than 15 %
10.3.2 Size—The prepared rock surface shall extend at least
of the plate diameter at any point. The dimensional require-
one-half the diameter of the bearing plate beyond the edge of
ments are shown in Fig. 4.
the plate.
10.3.3 Rock Quality—To the extent possible, prepare the 10.5 Displacement Measuring Points— Measure the dis-
bearing surface in sound rock. Remove loose and broken rock placementofthebearingplateinatleastthreelocationsequally
D4553–02 (2006)
Project _____________________________________________________________ Test No. _____________________________________
Feature ____________________________________________________________ Rock type ____________________________________
Test location ________________________________________________________ Plate diameter ________________________________
Orientation __________________________________________________________ Tested by ____________________________________
Sustain Load ________________________________________________
Equipment Serial Date of
description no. next calibration
______________________________________ ________________________________________ _____________________________________
_______________________________________ _________________________________________ _____________________________________
_______________________________________ _________________________________________ ______________________________________
_______________________________________ __________________________________________ _______________________________________
________________________________________ __________________________________________ _______________________________________
_________________________________________ __________________________________________ _______________________________________
__________________________________________ __________________________________________ ________________________________________
Plate displacement
Time Load Temperature No. 1 No. 2 No. 3
______________________ _________________ ______________________________ ________ ________ ________
______________________ ___
...