ASTM D4506-02(2006)
(Test Method)Standard Test Method for Determining the In Situ Modulus of Deformation of Rock Mass Using a Radial Jacking Test
Standard Test Method for Determining the In Situ Modulus of Deformation of Rock Mass Using a Radial Jacking Test
SIGNIFICANCE AND USE
Using this test method, a volume of rock large enough to take into account the influence of discontinuities on the properties of the rock mass is loaded. The test should be used when values are required which represent the true rock mass properties more closely than can be obtained through less expensive uniaxial jacking tests or other procedures.
Note 1—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 D 3740 are generally considered capable of competent and objective testing/sampling/inspection/etc. Users of this standard are cautioned that compliance with Practice D 3740 does not in itself assure reliable results. Reliable results depend on many factors; Practice D 3740 provides a means of evaluating some of those factors.
SCOPE
1.1 This test method is used to determine the in situ modulus of deformation of rock mass by subjecting a test chamber of circular cross section to uniformly distributed radial loading; the consequent rock displacements are measured, from which elastic or deformation moduli may be calculated. The anisotropic deformability of the rock can also be measured and information on time-dependent deformation may be obtained.
1.2 This test method is based upon the procedures developed by the U.S. Bureau of Reclamation featuring long extensometers (1). An alternative procedure is also available and is based on a reference bar (2).
1.3 Application of the test results is beyond the scope of this test method, but may be an integral part of some testing programs.
1.4 The values stated in inch-pound units are to be regarded as the standard.
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:D4506–02 (Reapproved 2006)
Standard Test Method for
Determining the In Situ Modulus of Deformation of Rock
Mass Using a Radial Jacking Test
This standard is issued under the fixed designation D 4506; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope* D 4403 Practice for Extensometers Used in Rock
1.1 This test method is used to determine the in situ
3. Terminology
modulus of deformation of rock mass by subjecting a test
3.1 Definitions: See Terminology D 653 for general defini-
chamber of circular cross section to uniformly distributed
tions.
radial loading; the consequent rock displacements are mea-
3.2 Definitions of Terms Specific to This Standard:
sured, from which elastic or deformation moduli may be
3.2.1 deformation—the change in the diameter of the exca-
calculated. The anisotropic deformability of the rock can also
vation in rock (test chamber).
be measured and information on time-dependent deformation
may be obtained.
4. Summary of Test Method
1.2 This test method is based upon the procedures devel-
4.1 A circular test chamber is excavated and a uniformly
oped by the U.S. Bureau of Reclamation featuring long
2 distributed pressure is applied to the chamber surfaces by
extensometers (1) . An alternative procedure is also available
means of flat jacks positioned on a reaction frame. Rock
and is based on a reference bar (2).
deformation is measured by extensometers placed in boreholes
1.3 Applicationofthetestresultsisbeyondthescopeofthis
perpendicular to the chamber surfaces. Pressure is measured
test method, but may be an integral part of some testing
with a standard hydraulic transducer. During the test, the
programs.
pressure is cycled incrementally and deformation is read at
1.4 The values stated in inch-pound units are to be regarded
each increment. The modulus is then calculated. To determine
as the standard.
time-dependent behavior, the pressure is held constant and
1.5 This standard does not purport to address all of the
deformation is observed over time.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
5. Significance and Use
priate safety and health practices and determine the applica-
5.1 Usingthistestmethod,avolumeofrocklargeenoughto
bility of regulatory limitations prior to use.
take into account the influence of discontinuities on the
properties of the rock mass is loaded. The test should be used
2. Referenced Documents
when values are required which represent the true rock mass
2.1 ASTM Standards:
properties more closely than can be obtained through less
D 653 Terminology Relating to Soil, Rock, and Contained
expensive uniaxial jacking tests or other procedures.
Fluids
D 3740 Practice for Minimum Requirements for Agencies
NOTE 1—The quality of the result produced by this standard is
Engaged in the Testing and/or Inspection of Soil and Rock dependent on the competence of the personnel performing it, and the
suitability of the equipment and facilities used. Agencies that meet the
as Used in Engineering Design and Construction
criteria of Practice D 3740 are generally considered capable of competent
and objective testing/sampling/inspection/etc. Users of this standard are
cautioned that compliance with Practice D 3740 does not in itself assure
ThistestmethodisunderthejurisdictionofASTMCommitteeD18onSoiland
reliable results. Reliable results depend on many factors; Practice D 3740
Rock and is the direct responsibility of Subcommittee D18.12 on Rock Mechanics.
provides a means of evaluating some of those factors.
Current edition approved May 1, 2006. Published June 2006. Originally
approved in 1985. Last previous edition approved in 2002 as D 4506 – 02.
6. Apparatus
The boldface numbers in parentheses refer to the list of references appended to
this standard.
6.1 ChamberExcavationEquipment—Thisincludesdrilling
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
and “smooth wall” blasting equipment or mechanical excava-
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
tion equipment capable of producing typically a 9-ft (3-m)
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. diameter tunnel with a length about three times that dimension.
*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.
D4506–02 (2006)
6.2 Concreting Equipment—Concreting materials and the maximum of the full circumference of the lining with
equipment for lining the tunnel, together with strips of weak sufficient separation to allow displacement measurements, and
jointing materials for segmenting the lining. should have a bursting pressure and travel consistent with the
6.3 Reaction Frame—The reaction frame shall be com- anticipatedloadsanddisplacements.Stainlesssteelflatjacksin
prised of steel rings of sufficient strength and rigidity to resist effective contact with 90 % of the area are recommended, with
the force applied by flat jacks, as depicted in Fig. 1. For load the maximum pressure capacity twice the design pressure.
application by flat jacks, the frame must be provided with 6.5 Load Measuring Equipment—Load measuring equip-
smooth surfaces; hardwood planks are usually inserted be- ment shall consist of one or more hydraulic pressure gages or
tween the flat jacks and the metal rings. transducers of suitable range, capable of measuring the applied
6.4 Loading Equipment, to apply a uniformly distributed pressurewithanaccuracybetterthan 62 %.Measurementsare
radial pressure to the inner face of the concrete lining, usually made by means of mechanical gages. Particular care is
including: required to guarantee the reliability of electric transducers and
6.4.1 Hydraulic Pump,withallnecessaryhoses,connectors, recording equipment, when used.
and fluid, capable of applying the required pressure and of 6.6 Displacement Measuring Equipment— Displacement
holding this pressure constant to within 5 % over a period of at measuring equipment to monitor rock movements radial to the
least 24 h. tunnel must have a precision better than 0.01 mm. Multiple-
6.4.2 Flat Jacks, used for load application (Fig. 1), of a position (six anchor points) extensometers in accordance with
practicable width and of a length equal at least to the diameter Practice D 4403 should be used. The directions of measure-
of the tunnel (9 ft (3m)). The jacks should be designed to load ment should be normal to the axis of the tunnel. Measurements
1. Measuring profile. 2. Distance equal to the length of active loading. 3. Control extensometer. 4. Pressure gage. 5. Reference beam. 6. Hydraulic pump. 7. Flat jack.
8.Hardwoodlagging.9.Shotcrete.10.Excavationdiameter.11.Measuringdiameter.12.Extensometerdrillholes.13.Dialgageextensometer.14.Steelrod.15.Expansion
wedges. 16. Excavation radius. 18. Inscribed Circle. 19. Rockbolt anchor. 20. Steel ring.
FIG. 1 Radial Jacking Test
D4506–02 (2006)
of movement should be related to reference anchors rigidly
secured in rock, well away from the influence of the loaded
zone. The multiple-position extensometers should have the
deepest anchor as a reference situated at least 3 test-chamber
diameters from the chamber lining.
7. Personnel Qualification and Equipment Calibration
7.1 All personnel involved in performing the test, including
the technicians and test supervisor, shall be formally prequali-
fied under the quality assurance procedures established as part
of the overall testing program.
7.2 The compliance of all equipment and apparatus with the
FIG. 2 Typical Graph of Applied Pressure Versus Displacement
performance specifications in Section 6 shall be verified.
Performance verification is generally done by calibrating the
equipment and measurement systems. Calibration and docu-
8.2.3 On reaching the maximum pressure for the cycle, hold
mentation shall be accomplished in accordance with standard
the pressure constant for 10 min. Complete each cycle by
quality assurance procedures.
reducing the pressure to near zero at the same average rate,
taking a further three sets of pressure-displacement readings.
8. Procedure
8.2.4 For the final cycle, hold the maximum pressure
8.1 Test Chamber:
constant for 24 h to evaluate creep. Complete the cycle by
8.1.1 Select the test chamber location taking into consider-
unloading in stages, taking readings of pressure and corre-
ation the rock conditions, particularly the orientation of the
sponding displacements similar to the loading cycle.
rock mass elements such as joints, bedding, and foliation in
relationtotheorientationoftheproposedtunneloropeningfor
9. Calculation
which results are required.
9.1 Correct the applied load values to give an equivalent
8.1.2 Excavate the test chamber by smooth (presplit) blast-
distributed pressure, p , on the test chamber lining, as follows:
ing to the required diameter of 9 ft (3 m), with a length equal
(b
to at least three diameters.
p 5 ·p (1)
1 m
2·p·r
8.1.3 Record the geology of the chamber and specimens
taken for index testing, as required. Core and log all instru-
where:
mentation holes as follows:
p = distributed pressure on the lining at r , psi (MPa),
1 1
r = radius, ft (m),
8.1.3.1 Cored Boreholes—Drill the boreholes using dia-
p = pressure in the flat jacks, psi (MPa), and
m
mond core techniques. Continuous core shall be obtained.
b = flat jack width (see Fig. 3), ft (m).
8.1.3.2 Core Logged—Completely log the recovered core,
9.1.1 Calculate the equivalent pressure p at a “measuring
with emphasis on fractures and other mechanical nonhomoge-
radius” r just beneath the lining; this radius being outside the
neities.
zone of irregular stresses beneath the flat jacks and the lining
8.1.4 Accurately mark out and drill the extensometer holes,
and loose rock (see Fig. 3).
ensuring no interference between loading and measuring sys-
r (b
tems. Install six-point extensometers and check the equipment.
P 5 ·P 5 ·P (2)
2 1 m
r 2· p·r
2 2
Place two anchors deep beyond the tunnel influence, appropri-
P (b 5 P ·2· r · p
ately spacing the other four anchors as close to the surface of
m 1 1
the tunnel as possible.
P (b
m
P 5
2· p · r
8.1.5 Assemble the reaction frame and loading equipment.
r
8.1.6 Line the chamber with concrete to fill the space
P 5 P
2 1
r
between the frame and the rock.
8.2 Loading:
9.2 Superposition is only strictly valid for elastic deforma-
8.2.1 Perform the test with at least three loading and tions but also gives a good approximation if the rock is
unloading cycles, a higher maximum pressure being applied at
moderately plastic in its behavior. Superposition of displace-
each cycle. Typically, the maximum pressure applied is 1000 ments for two fictitious loaded lengths is used to give the
psi (7 MPa), depending on expected loads.
equivalent displacements for an “infinitely long test chamber.”
This superposition is made necessary by the comparatively
8.2.2 Foreachcycle,increasethepressureatanaveragerate
short length of the test chamber in relation to its diameter.
of 100 psi/min (0.7 MPa/min) to the maximum for the cycle,
taking not less than 10 intermediate sets of load-displacement 9.3 Plot the result of the long duration test, D under
d
readings in order to define a set of pressure-displacement maximum pressure, max P , on the displacement graph (Fig.
curves (see Fig. 2). The automation of data recording is 4). Proportionally correct test data for each cycle to give the
recommended. complete long-term pressure-displacement curve. The elastic
D4506–02 (2006)
n = estimated value for Poisson’s Ratio.
9.4.1 As an alternative to 9.4, the moduli of undisturbed
rock may be obtained, taking into account the effect of a
fissured and loosened region, by using the following formulae:
p ·r n1 1 r
2 2 3
E 5 · 1 ln (5)
S D
D n r
e 2
p ·r n1 1 r
2 2 3
D 5 · 1 ln
S D
D n r
t 2
where:
r = radius to the limit of the assumed fissured and
loosened zone, ft (m), and
ln = natural logarithm.
9.4.2 Assumptions—This solution is given for the case of a
single measuring circle with extensometer anchors immedi-
ately behind the lining. The solution assumes linear-elastic
behavior for the rock and is usually adequate in practice,
although it is possible to analyze more complex test configu-
rations (using, for example, a finite element analysis).
10. Report
10.1 Thepurposeofthissectionistoestablishtheminimum
requirements for a complete and usable report. Further details
may be added as appropriate, and the order of items may be
FIG. 3 Scheme of Loading Showing Symbols Used in the
changed. If application of the test results is part of the testing
Calculations
program, an application section compatible with the format
described below should be included. The report shall include
the following:
10.1.1 Introductory Section—The introductory section is
intended to present the scope and purpose of the testing
program and the characteristics of the material tested, as
follows:
10.1.1.1 Scope—This shall include (1) the location and
orientation of the test boreholes (a graphic presentation is
recommended), (2) the reasons for selecting the test locations,
and (3) in general terms, a discussion of the limitations of the
testing program, that is, the areas of interest not covered by the
testing program and the limitations of the data within the areas
of application.
10.1.2 Brief Description of the Test Site Geology—Describe
FIG. 4 Typical Graph Showing Total and Plastic Displacements as
a Function of Direction Perpendicular to the Test Chamber Axis
the rock type macroscopically from both field inspection and
from the core logs of the test boreholes. Discuss structural
featuresaffectingthetesting,asappropriate.Includealistingof
component, D , and the plastic component, D , of the total
e p
the types of data available on properties of the rock cores
deformation, D, are obtained from the deformation at the final
t
containing such property data as may aid interpretation of the
unloading:
test data (for example, rock quality designation (RQD), labo-
D 5D 1D ~see Fig.4! (3)
t p e
ratory tests of strength and deformation).
9.4 The elastic modulus, E, and the deformation modulus,
10.1.3 Test Method Section:
D, are obtained from the pressure-displacement graph (Fig. 2)
10.1.3.1 Equipment and
...
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