ASTM D5321-92(1997)
(Test Method)Standard Test Method for Determining the Coefficient of Soil and Geosynthetic or Geosynthetic and Geosynthetic Friction by the Direct Shear Method
Standard Test Method for Determining the Coefficient of Soil and Geosynthetic or Geosynthetic and Geosynthetic Friction by the Direct Shear Method
SCOPE
1.1 This test method covers a procedure for determining the shear resistance of a geosynthetic against soil, another geosynthetic, or a soil and geosynthetic in any combination.
1.1.1 The test method is intended to indicate the performance of the selected specimen by attempting to model certain field conditions.
1.2 The test method is applicable for all geosynthetics. Remolded or undisturbed soil samples can be used in the test device.
1.3 The test method is not suited for the development of exact stress-strain relationships within the test specimen due to the non-uniform distribution of shearing forces and displacement.
1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.5 This standard does not purport to address all of the safety problems, 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.
General Information
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Standards Content (Sample)
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Designation: D 5321 – 92 (Reapproved 1997)
Standard Test Method for
Determining the Coefficient of Soil and Geosynthetic or
Geosynthetic and Geosynthetic Friction by the Direct Shear
Method
This standard is issued under the fixed designation D 5321; 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 4439 Terminology for Geosynthetics
1.1 This test method covers a procedure for determining the
3. Terminology
shear resistance of a geosynthetic against soil, another geosyn-
3.1 Definitions—For definitions of terms relating to soil and
thetic, or a soil and geosynthetic in any combination.
rock, refer to Terminology D 653. For definitions of terms
1.1.1 The test method is intended to indicate the perfor-
relating to geosynthetics, refer to Terminology D 4439.
mance of the selected specimen by attempting to model certain
3.2 Descriptions of Terms Specific to This Standard:
field conditions.
−2
3.2.1 adhesion, (FL ), n—the shearing resistance be-
c
1.2 The test method is applicable for all geosynthetics.
a
tween soil and another material under zero externally applied
Remolded or undisturbed soil samples can be used in the test
pressure. (D 653, D-18)
device.
3.2.2 angle of friction, n—(angle of friction between solid
1.3 The test method is not suited for the development of
bodies) (degrees) the angle whose tangent is the ratio between
exact stress-strain relationships within the test specimen due to
the maximum value of the shear stress that resists slippage
the non-uniform distribution of shearing forces and displace-
between two solid bodies at rest with respect to each other and
ment.
the normal stress across the contact surface. (D 653, D-18)
1.4 The values stated in SI units are to be regarded as the
3.2.3 atmosphere for testing geosynthetics, n—air main-
standard. The values given in parentheses are for information
tained at a relative humidity of 65 6 5 % and temperature of
only.
21 6 2°C (70 6 4°F). (D 4439)
1.5 This standard does not purport to address all the safety
3.2.4 coeffıcient of friction, n—a constant proportionality
concerns, if any, associated with its use. It is the responsibility
factor, relating normal stress and the corresponding critical
of the user of this standard to establish appropriate safety and
shear stress, at which sliding starts between two surfaces.
health practices and determine the applicability of regulatory
(D 653, D-18)
limitations prior to use.
3.2.5 direct shear friction test, n—for geosynthetics, a
2. Referenced Documents procedure in which the interface between a geosynthetic and
any other surface, under a range of normal stresses specified by
2.1 ASTM Standards:
the user, is stressed to failure by the horizontal movement of
D 653 Terminology Relating to Soil, Rock and Contained
one surface against the other.
Fluids
3.2.6 geosynthetic, n—a planar synthetic product manufac-
D 698 Test Method for Laboratory Compaction Character-
tured from polymeric material used with soil, rock, earth, or
istics of Soil Using Standard Effort (12 400 ft/lbf/ft (600
2 other geotechnical engineering-related material as an integral
kN/m/m ))
part of a man-made project, structure, or system. (D 4439)
D 1557 Test Method for Laboratory Compaction Character-
istics of Soil Using Modified Effort (56 000 ft-lbf/ft (2700
4. Summary of Test Method
3 2
kN/m/m )
4.1 The coefficient of friction between a geosynthetic and
D 3080 Test Method for Direct Shear Test of Soils Under
2 soil, or between any geosynthetic combination selected by the
Consolidated Drained Conditions
3 user, is determined by placing the geosynthetic and one or
D 4354 Practice for Sampling of Geotextiles for Testing
more contact surfaces, such as soil, within a direct shear box.
A constant normal compressive stress is applied to the speci-
This test method is under the jurisdiction of ASTM Committee D-35 on
men, and a tangential (shear) force is applied to the apparatus
Geosynthetics and is the direct responsibility of Subcommittee D35.01 on Mechani-
so that one section of the box moves in relation to the other
cal Properties.
section. The shear force is recorded as a function of the
Current edition approved Oct. 15, 1992. Published December 1992.
Annual Book of ASTM Standards, Vol 04.08.
horizontal displacement of the moving section of the shear box.
Annual Book of ASTM Standards, Vol 04.09.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
D 5321
The test is performed for a minimum of three different normal 6. Apparatus
stresses, selected by the user, to model appropriate field
6.1 Shear Device—A rigid device to hold the specimen
conditions. The peak (or alternatively, the residual) shear
securely and in such a manner that a uniform force without
stresses recorded are plotted against the applied normal com-
torque can be applied to the specimen. The device consists of
pressive stresses used for testing. The test data are generally
both a stationary and moving container, both of which are
represented by a best fit straight line whose slope is the
capable of containing dry or wet soil and are rigid enough to
coefficient of friction between the two materials where the
prevent distortion during shearing of the specimen. The trav-
shearing occurred. The y-intercept of the straight line is the
eling container must be placed on firm bearings and rack to
adhesion.
ensure that the movement of the container is only in a direction
parallel to that of the applied shear force.
5. Significance and Use
NOTE 3—One container should be adjustable to compensate for defor-
5.1 The procedure described in this test method for deter-
mation of the soil.
mination of the coefficient of soil and geosynthetic or geosyn-
6.1.1 Square or rectangular containers are recommended;
thetic and geosynthetic friction by the direct shear method is
they should have a minimum dimension that is the greater of
intended as a performance test to provide the user with a set of
300 mm (12 in.), 15 times the d of the coarser soil used in the
design values for the test conditions examined. The test 85
test, or a minimum of five times the maximum opening size (in
specimens and parameters are generally selected by the user.
plan) of the geosynthetic tested. The depth of each container
5.2 This test method may be used for acceptance testing of
should be 50 mm (2 in.) or six times the maximum particle size
commercial shipments of geosynthetics, but caution is advised
of the coarser soil tested, whichever is greater. The minimum
as outlined below.
specimen to width to thickness ratio is 2:1.
5.2.1 The coefficient of soil and geosynthetic friction can be
expressed only in terms of the soil used in testing (see Notes 1
NOTE 4—The minimum container dimensions given in 6.1.1 are guide-
lines based on requirements for testing most combinations of geosynthet-
and 2). The coefficient of friction is a function of the applied
ics and soils. Containers smaller than those specified in 6.1.1 can be used
normal compressive stress, soil gradation, plasticity, in-place
if it can be shown that data generated by the smaller devices contain no
density, moisture content, and other parameters.
scale or edge effects bias when compared to the minimum size devices
specified in 6.1.1. The user should conduct comparative testing prior to the
NOTE 1—In the case of acceptance testing requiring the use of soil, the
acceptance of data produced on smaller devices. For direct shear testing
user must furnish the soil sample, soil parameters, and direct shear test
involving soils, competent geotechnical review is recommended to evalu-
parameters.
ate the compatibility of the minimum and smaller direct shear devices.
NOTE 2—Soil and geosynthetic friction tests should be performed by
laboratories experienced in the friction testing of soils, especially since the
6.2 Normal Stress Loading Device, capable of applying and
test results may be dependent on site-specific soil conditions.
maintaining a constant uniform normal stress on the specimen
5.2.2 This test method measures the total resistance to
for the duration of the test. Careful control and accuracy
sliding of a geosynthetic with a supporting material (substra-
(62 %) of the normal stress is important. Normal stress
tum) or an overlying material (superstratum). Total sliding
loading devices include, but are not limited to, weights,
resistance may be a combination of sliding, rolling, interlock-
pneumatic or hydraulic bellows, or piston-applied stresses. For
ing of soil particles and geosynthetic surfaces, and shear strain
jacking systems, the tilting of loading plates must be limited to
within the geosynthetic specimen.
10 mm (0.4 in.) from the center to the edge of the plate during
5.2.3 The test method does not distinguish between indi-
operation of the test device.
vidual mechanisms, which may be a function of the soil used,
6.3 Shear Force Loading Device, capable of applying a
method of soil placement, normal and shear stresses applied,
shearing force to the specimen at a constant rate of displace-
rate of horizontal displacement, and other factors. Every effort
ment (strain controlled) in a direction parallel to the direction
should be made to identify, as closely as is practicable, the of travel of the soil container. The rate of displacement should
sheared area and failure mode of the specimen so that
be controlled to an accuracy of 610 % over a wide range of
comparison tests can be performed. Care should be taken, displacements. The system must allow constant measurement
including close visual inspection of the specimen after testing,
and readout of the shear force applied. An electronic load cell
to ensure that the testing conditions are representative of those or proving ring arrangement is generally used. The shear force
being investigated.
loading device should be connected to the test apparatus in
5.2.4 Information on precision between laboratories is in- such a fashion that the point of the load application to the
complete. In cases of dispute, comparative tests to determine
traveling container is in the plane of the shearing interface and
whether a statistical bias exists between laboratories may be remains the same for all tests.
advisable.
6.4 Displacement Indicators, for providing continuous read-
5.3 The test method produces test data that can be used as out of the horizontal shear displacement and, if desired, vertical
follows: in the design of geosynthetic-reinforced retaining displacement of the specimen during the consolidation or shear
walls, embankments, and base courses; in applications in phase. Dial indicators, or linear variable differential transform-
which the geosynthetic is placed on a slope; for determination ers (LVDT), capable of measuring a displacement of at least 75
of geosynthetic overlap requirements; or in other applications mm (3 in.) for horizontal displacement and 25 mm (1 in.) for
in which soil/geosynthetic or geosynthetic/geosynthetic fric- vertical displacement are recommended. The sensitivity of
tion is critical to design. displacement indicators should be 0.02 mm (0.001 in.) for
NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
D 5321
measuring horizontal displacement. edge of the geosynthetic production unit than ⁄10 the width of
the unit.
6.5 Geosynthetic Clamping Devices, required for fixing
geosynthetic specimens to the stationary section or container,
NOTE 6—Lots for geosynthetics are usually designated by the producer
the traveling container, or both, during shearing of the speci-
during manufacturer. While the test method does not attempt to establish
men. Clamps shall not interfere with the shearing surfaces
a frequency of testing for the determination of design-oriented data, the lot
within the shear box and must keep the geosynthetic specimens number of the laboratory sample should be identified. The lot number
should be unique to the raw material and manufacturing process for a
flat during testing. Flat jaw-like clamping devices are normally
specific number of units (for example, rolls, panels, etc.) designated by the
sufficient. Gluing of the geosynthetic specimen to a substrate
producer.
(such as wood), which is placed in either or both of the soil
NOTE 7—The frictional characteristics of some geosynthetics may
containers, is an acceptable clamping technique, provided that
depend on the direction tested. In many applications, it is necessary to
soil is not used along with the wooden substrate and it does not
perform shear test in only one direction. The direction of shear in the
interfere with the test operation or that the glue does not change
geosynthetic specimen(s) must be noted clearly in these cases.
the shearing properties of the geosynthetic specimen. If gluing
8. Shear Device Calibration
is used, the specimen should be checked carefully to ensure
that shearing of the glued surface does not occur. A trial test is 8.1 The direct shear device is calibrated to measure the
recommended to establish the proper type of glue and setting internal resistance to shear inherent to the device. The inherent
shear resistance is a function of the geometry and mass of the
time.
traveling container, type and condition of the bearings, and
NOTE 5—The selection of specimen substrate may influence the test
type of shear loading system.
results. For instance, a test performed using a rigid substrate, such as a
8.2 Assemble the shear device completely without placing a
wood or metal plate, may not simulate field conditions as accurately as
specimen inside it. Do not apply a normal stress. Apply the
that using a soil substrate. The user should be aware of the influence of
substrate on direct shear friction data. Accuracy and reproducibility should shear force to the traveling container at a rate of 10 mm/min
be considered when selecting a substrate for testing.
(0.5 in./min). Record the shear force required to sustain
movement of the traveling container for at least 50 mm (2 in.)
6.6 Soil Preparation Equipment, for preparing or compact-
total horizontal displacement. Record any large variation in
ing bulk soil samples, as outlined in Test Methods D 698 or
applied s
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