ASTM D8359-20
(Test Method)Standard Test Method for Determining the In Situ Rock Deformation Modulus and Other Associated Rock Properties Using a Flexible Volumetric Dilatometer
Standard Test Method for Determining the In Situ Rock Deformation Modulus and Other Associated Rock Properties Using a Flexible Volumetric Dilatometer
SIGNIFICANCE AND USE
5.1 The dilatometer test is usually performed in vertical boreholes. It can be used in inclined or horizontal holes, but the probe would drag along the borehole wall.
5.2 Deformation modulus of rock, creep characteristics, rebound, and permanent set data is obtained and is useful for engineering designs.
5.3 The rock mass discontinuities, in situ stresses, and the genesis, crystallography, texture, fabric, and other factors may cause the rock mass to behave as an anisotropic, inhomogeneous, discontinuous medium that laboratory size tests may not be able to measure that the dilatometer may be able to measure.
5.4 Determination of rock mass deformability yields a critical parameter in the design of foundations of dams, support of underground excavations, piers, caissons, and stability of rock slopes.
Note 2: Although a rock mass behaves in an anisotropic and inhomogeneous manner, the calculations for a rock mass deformation modulus are based on assumptions of elasticity and homogeneity. However, they still render results that are practical, simple, usable, and not significantly different from those obtained using inhomogeneity and inelasticity.
Note 3: The existing in situ stresses can only be estimated by in situ tests on the rock mass, such as this or other tests.
5.5 In situ tests such as this one provides general information regarding rock mass behavior. Dilatometer tests are advised when designing and constructing specific structures.
5.6 Dilatometer tests can be performed at a reasonable cost and effort. Dilatometer tests are also less expensive and time-consuming compared to other deformability tests like radial jack or flexible plate tests that require underground excavation and access too.
5.7 Dilatometer modulus can be correlated with the moduli obtained by other methods (for example, the plate loading or radial jacking methods). The correlated dilatometer modulus can then be used instead of other more expensive in situ modulus tests. ...
SCOPE
1.1 This test method establishes the guidelines, requirements, procedure, and analyses for determining the in situ deformation modulus of a rock mass and other ancillary data using a flexible volumetric dilatometer in an NX drill hole (Fig. 1). Cyclic, creep, and unloading cycles are not covered in detail in this standard but may be added in the future or with a separate test standard, practice, or guide.
FIG. 1 General Depiction of a Flexible Dilatometer in a Borehole
Note 1: Other rock mass deformability tests are radial jack tests, flat jack tests, flexible plate tests, and borehole jack tests.
1.2 This test method applies mainly to a commercially available flexible, volumetric dilatometer for an NX-sized (75.7-mm (2.98-in.)) borehole that is inflated and deflated hydraulically in the borehole. However, the test method could apply to other dilatometers, including pneumatically inflated, or for different borehole sizes as well as covered under the British Standards Institute EN ISO 22476-5.
1.3 Purpose, Application, Range of Uses, and Limitations:
1.3.1 This designation is described in the context of obtaining data for the design, construction, or maintenance of structures on or in rock. This method can be conducted in any orientation but is usually conducted in a vertical or horizontal borehole as dictated by the design consideration.
1.3.2 The test has no depth limits other than those imposed by the limitations of the test equipment, drill hole quality, testing personnel, and equipment to drill the holes and position the testing assembly.
1.3.3 Since this is a volumetric test, only the average deformation is obtained around the borehole. If the rock properties, for any reason, including the in situ stress field or fracture density, are significantly anisotropic, then this device cannot detect that difference.
1.3.4 A large expansion of the probe in a test zone can occur due to either an oversi...
General Information
Standards Content (Sample)
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: D8359 − 20
Standard Test Method for
Determining the In Situ Rock Deformation Modulus and
Other Associated Rock Properties Using a Flexible
1
Volumetric Dilatometer
This standard is issued under the fixed designation D8359; 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 discontinuities.As a result, the maximum pressure and expan-
sion of the dilatometer would be limited. For example, for one
1.1 This test method establishes the guidelines,
particular dilatometer to avoid damaging the membrane in a
requirements, procedure, and analyses for determining the in
preferred N size, 75.7 mm (2.98 in.) boreholes, the maximum
situ deformation modulus of a rock mass and other ancillary
working pressure of 30,000 kPa might be possible. In contrast,
data using a flexible volumetric dilatometer in an NX drill hole
at 82.5 mm, the maximum working pressure would drop to
(Fig. 1). Cyclic, creep, and unloading cycles are not covered in
only 20,680 kPa. Furthermore, regardless of if it an oversized
detail in this standard but may be added in the future or with a
drill hole or a low modulus test interval, the maximum
separate test standard, practice, or guide.
diameter (inflated) of only 85.5 mm is allowed.
NOTE 1—Other rock mass deformability tests are radial jack tests, flat
1.3.5 The radial displacements of the borehole walls during
jack tests, flexible plate tests, and borehole jack tests.
pressurization are calculated from the total volume change of
1.2 This test method applies mainly to a commercially
the dilatometer. As such, the test results from a volumetric
available flexible, volumetric dilatometer for an NX-sized
dilatometerindicatesonlytheaveragedvalueofthemodulusof
(75.7-mm (2.98-in.)) borehole that is inflated and deflated
deformation.
hydraulically in the borehole. However, the test method could
1.3.6 The volumetric dilatometer test does not provide the
apply to other dilatometers, including pneumatically inflated,
anisotropic properties of the rock mass because it measures the
or for different borehole sizes as well as covered under the
average deformation and not the deformation in specific
British Standards Institute EN ISO 22476-5.
directions. However, by conducting dilatometer tests in bore-
1.3 Purpose, Application, Range of Uses, and Limitations:
holes oriented in different directions or taking impression
1.3.1 This designation is described in the context of obtain-
packer data in any test intervals that had developed a hydraulic
ing data for the design, construction, or maintenance of
type fracture, some aspects of the in situ anisotropic conditions
structures on or in rock. This method can be conducted in any
could be obtained.
orientation but is usually conducted in a vertical or horizontal
1.4 Units—The values stated in SI units are to be regarded
borehole as dictated by the design consideration.
as standard. The values given in parentheses are provided for
1.3.2 The test has no depth limits other than those imposed
information only and are not considered standard. Reporting of
by the limitations of the test equipment, drill hole quality,
test results in units other than SI shall not be regarded as
testing personnel, and equipment to drill the holes and position
nonconformance with this standard.
the testing assembly.
1.4.1 The gravitational system of inch-pound units is used
1.3.3 Since this is a volumetric test, only the average
when dealing with inch-pound units. In the system, the pound
deformation is obtained around the borehole. If the rock
(lbf) represents a unit of force (weight), while the units for
properties, for any reason, including the in situ stress field or
mass is slugs. The slug unit is not given, unless dynamic (F =
fracture density, are significantly anisotropic, then this device
ma) calculations are involved.
cannot detect that difference.
1.3.4 Alargeexpansionoftheprobeinatestzonecanoccur
1.5 All observed and calculated values shall conform to the
due to either an oversized drill hole, weathering, lithology, or
guidelines for significant digits and rounding established in
Practice D6026.
1.5.1 Theproceduresusedtospecifyhowdataarecollected/
1
These test methods are under the jurisdiction ofASTM Committee D18 on Soil
recorded or calculated in the standard are regarded as the
and Rock and are the direct responsibility of Subcommittee D18.12 on Rock
industry standard. In addition, they are representative of the
Mechanics.
significant digits that generally should be retained. The proce-
Current edition approved Nov. 1, 2020. Published December 2020. DOI:
10.1520/D83
...
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