ASTM D4506-90(1995)

Standard Test Method for Determining the In Situ Modulus of Deformation of Rock Mass Using a Radial Jacking Test

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.  
1.5 This standard does not purport to address the safety problems 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.

General Information

• Status: Historical
• Publication Date: 31-Dec-1994
• ICS: 93.020 - Earthworks. Excavations. Foundation construction. Underground works
• Technical Committee: D18 - Soil and Rock
• Drafting Committee: D18.12 - Rock Mechanics

Relations

• Replaced By: ASTM D4506-02 - Standard Test Method for Determining the In Situ Modulus of Deformation of Rock Mass Using a Radial Jacking Test
• Effective Date: 10-Jan-2002

Standards Content (Sample)

Designation: D 4506 – 90 (Reapproved 1995)
AMERICAN SOCIETY FOR TESTING AND MATERIALS
100 Barr Harbor Dr., West Conshohocken, PA 19428
Reprinted from the Annual Book of ASTM Standards. Copyright ASTM
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 equal to the slope of the tangent or the secant of a stress-strain
curve. The use of the term modulus of elasticity is recom-
1.1 This test method is used to determine the in situ
mended for materials that deform in accordance with Hooke’s
modulus of deformation of rock mass by subjecting a test
law; the term modulus of deformation for materials that deform
chamber of circular cross section to uniformly distributed
otherwise (from Terminology D 653).
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 Application of the test results is beyond the scope of this
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 Using this test method, a volume of rock large enough to
bility of regulatory limitations prior to use.
take into account the influence of discontinuities on the
2. Referenced Documents properties of the rock mass is loaded. The test should be used
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
3 expensive uniaxial jacking tests or other procedures.
Fluids
D 4403 Practice for Extensometers Used in Rock
6. Apparatus
3. Terminology 6.1 Chamber Excavation Equipment—This includes drilling
and “smooth wall” blasting equipment or mechanical excava-
3.1 Definitions:
tion equipment capable of producing typically a 9-ft (3-m)
3.1.1 deformation—change in shape or size (from Termi-
diameter tunnel with a length about three times that dimension.
nology D 653) (see 3.2.1).
6.2 Concreting Equipment—Concreting materials and
3.1.2 modulus of deformation—the ratio of stress to strain
equipment for lining the tunnel, together with strips of weak
for a material under given loading conditions; numerically
jointing materials for segmenting the lining.
6.3 Reaction Frame—The reaction frame shall be com-
This test method is under the jurisdiction of ASTM Committee D-18 on Soil
prised of steel rings of sufficient strength and rigidity to resist
and Rock and is the direct responsibility of Subcommittee D18.12 on Rock
the force applied by flat jacks, as depicted in Fig. 1. For load
Mechanics.
Current edition approved May 25, 1990. Published July 1990. Originally application by flat jacks, the frame must be provided with
published as D 4506 – 85. Last previous edition D 4506 – 85.
smooth surfaces; hardwood planks are usually inserted be-
The boldface numbers in parentheses refer to the list of references appended to
tween the flat jacks and the metal rings.
this standard.
6.4 Loading Equipment, to apply a uniformly distributed
Annual Book of ASTM Standards, Vol 04.08.
D 4506
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. Hardwood lagging. 9. Shotcrete. 10. Excavation diameter. 11. Measuring diameter. 12. Extensometer drillholes. 13. Dial gage extensometer. 14. Steel rod. 15. Expansion
wedges. 16. Excavation radius. 18. Inscribed Circle. 19. Rockbolt anchor. 20. Steel ring.
FIG. 1 Radial Jacking Test
radial pressure to the inner face of the concrete lining, required to guarantee the reliability of electric transducers and
including: recording equipment, when used.
6.4.1 Hydraulic Pump, with all necessary hoses, connectors, 6.6 Displacement Measuring Equipment—Displacement
and fluid, capable of applying the required pressure and of measuring equipment to monitor rock movements radial to the
holding this pressure constant to within 5 % over a period of at tunnel must have a precision better than 0.01 mm. Multiple-
least 24 h. position (six anchor points) extensometers in accordance with
6.4.2 Flat Jacks, used for load application (Fig. 1), of a Practice D 4403 should be used. The directions of measure-
practicable width and of a length equal at least to the diameter ment should be normal to the axis of the tunnel. Measurements
of the tunnel (9 ft (3m)). The jacks should be designed to load of movement should be related to reference anchors rigidly
the maximum of the full circumference of the lining with secured in rock, well away from the influence of the loaded
sufficient separation to allow displacement measurements, and zone. The multiple-position extensometers should have the
should have a bursting pressure and travel consistent with the deepest anchor as a reference situated at least 3 test-chamber
anticipated loads and displacements. Stainless steel flat jacks in diameters from the chamber lining.
effective contact with 90 % of the area are recommended, with
7. Personnel Qualification and Equipment Calibration
the maximum pressure capacity twice the design pressure.
6.5 Load Measuring Equipment—Load measuring equip- 7.1 All personnel involved in performing the test, including
ment shall consist of one or more hydraulic pressure gages or the technicians and test supervisor, shall be formally prequali-
transducers of suitable range, capable of measuring the applied fied under the quality assurance procedures established as part
pressure with an accuracy better than 62 %. Measurements are of the overall testing program.
usually made by means of mechanical gages. Particular care is 7.2 The compliance of all equipment and apparatus with the
D 4506
performance specifications in Section 6 shall be verified. the pressure constant for 10 min. Complete each cycle by
Performance verification is generally done by calibrating the reducing the pressure to near zero at the same average rate,
equipment and measurement systems. Calibration and docu- taking a further three sets of pressure-displacement readings.
mentation shall be accomplished in accordance with standard 8.2.4 For the final cycle, hold the maximum pressure
quality assurance procedures. constant for 24 h to evaluate creep. Complete the cycle by
unloading in stages, taking readings of pressure and corre-
8. Procedure
sponding displacements similar to the loading cycle.
8.1 Test Chamber:
9. Calculation
8.1.1 Select the test chamber location taking into consider-
9.1 Correct the applied load values to give an equivalent
ation the rock conditions, particularly the orientation of the
distributed pressure, p , on the test chamber lining, as follows:
rock mass elements such as joints, bedding, and foliation in
relation to the orientation of the proposed tunnel or opening for
(b
p 5 ·p (1)
1 m
which results are required.
2·p·r
8.1.2 Excavate the test chamber by smooth (presplit) blast-
where:
ing to the required diameter of 9 ft (3 m), with a length equal
p 5 distributed pressure on the lining at r , psi (MPa),
1 1
to at least three diameters.
r 5 radius, ft (m),
8.1.3 Record the geology of the chamber and specimens
p 5 pressure in the flat jacks, psi (MPa), and
m
taken for index testing, as required. Core and log all instru-
b 5 flat jack width (see Fig. 3), ft (m).
mentation holes as follows:
9.1.1 Calculate the equivalent pressure p at a “measuring
8.1.3.1 Cored Boreholes—Drill the boreholes using dia-
radius” r just beneath the lining; this radius being outside the
mond core techniques. Continuous core shall be obtained.
zone of irregular stresses beneath the flat jacks and the lining
8.1.3.2 Core Logged—Completely log the recovered core,
and loose rock (see Fig. 3).
with emphasis on fractures and other mechanical nonhomoge-
r (b
neities.
P 5 ·P 5 ·P (2)
2 1 m
r 2· p·r
2 2
8.1.4 Accurately mark out and drill the extensometer holes,
P (b 5 P ·2· r · p
ensuring no interference between loading and measuring sys-
m 1 1
tems. Install six-point extensometers and check the equipment.
P (b
m
P 5
Place two anchors deep beyond the tunnel influence, appropri-
2· p · r
ately spacing the other four anchors as close to the surface of
r
P 5 P
the tunnel as possible. 2 1
r
8.1.5 Assemble the reaction frame and loading equipment.
9.2 Superposition is only strictly valid for elastic deforma-
8.1.6 Line the chamber with concrete to fill the space
tions but also gives a good approximation if the rock is
between the frame and the rock.
8.2 Loading:
8.2.1 Perform the test with at least three loading and
unloading cycles, a higher maximum pressure being applied at
each cycle. Typically, the maximum pressure applied is 1000
psi (7 MPa), depending on expected loads.
8.2.2 For each cycle, increase the pressure at an average rate
of 100 psi/min (0.7 MPa/min) to the maximum for the cycle,
taking not less than 10 intermediate sets of load-displacement
readings in
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