ASTM D3999-91(1996)
(Test Method)Standard Test Methods for the Determination of the Modulus and Damping Properties of Soils Using the Cyclic Triaxial Apparatus
Standard Test Methods for the Determination of the Modulus and Damping Properties of Soils Using the Cyclic Triaxial Apparatus
SCOPE
1.1 These test methods cover the determination of the modulus and damping properties of soils in either undisturbed or reconstituted states by either load or stroke controlled cyclic triaxial techniques.
1.2 The cyclic triaxial properties of soil are evaluated relative to a number of factors including: strain level, density, number of cycles, material type, saturation, and effective stress.
1.3 These test methods are applicable to both fine-grained and coarse-grained soils as defined by the unified soil classification system or by Classification D2487. Test specimens may be undisturbed or reconstituted by compaction in the laboratory.
1.4 Two test methods are provided for using a cyclic loader to determine Young's modulus (E) and damping (D) properties. The first test method (A) permits the determination of E and D using a constant load apparatus. The second test method (B) permits the determination of E and D using a constant stroke apparatus. The test methods are as follows:
1.4.1 Test Method A -This test method requires the application of a constant cyclic load to the test specimen. It is used for determining the Young's modulus and damping under a constant load condition.
1.4.2 Test Method B -This test method requires the application of a constant cyclic deformation to the test specimen. It is used for determining the Young's modulus and damping under a constant stroke condition.
1.5 The development of relationships to aid in interpreting and evaluating test results are left to the engineer or office requesting the test.
1.6 Limitations -There are certain limitations inherent in using cyclic triaxial tests to simulate the stress and strain conditions of a soil element in the field during an earthquake.
1.6.1 Nonuniform stress conditions within the test specimen are imposed by the specimen end platens.
1.6.2 A 90° change in the direction of the major principal stress occurs during the two halves of the loading cycle on isotropically confined specimens and at certain levels of cyclic stress application on anisotropically confined specimens.
1.6.3 The maximum cyclic axial stress that can be applied to a saturated specimen is controlled by the stress conditions at the end of confining stress application and the pore-water pressures generated during testing. For an isotropically confined specimen tested in cyclic compression, the maximum cyclic axial stress that can be applied to the specimen is equal to the effective confining pressure. Since cohesionless soils are not capable of taking tension, cyclic axial stresses greater than this value tend to lift the top platen from the soil specimen. Also, as the pore-water pressure increases during tests performed on isotropically confined specimens, the effective confining pressure is reduced, contributing to the tendency of the specimen to neck during the extension portion of the load cycle, invalidating test results beyond that point.
1.6.4 While it is advised that the best possible undisturbed specimens be obtained for cyclic testing, it is sometimes necessary to reconstitute soil specimens. It has been shown that different methods of reconstituting specimens to the same density may result in significantly different cyclic behavior. Also, undisturbed specimens will almost always be stronger than reconstituted specimens of the same density.
1.6.5 The interaction between the specimen, membrane, and confining fluid has an influence on cyclic behavior. Membrane compliance effects cannot be readily accounted for in the test procedure or in interpretation of test results. Changes in pore-water pressure can cause changes in membrane penetration in specimens of cohesionless soils. These changes can significantly influence the test results.
1.6.6 Despite these limitations, with due consideration for the factors affecting test results, carefully conducted cyclic triaxial tests can provide data on the cyclic behavior of soils with a...
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Standards Content (Sample)
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Designation: D 3999 – 91 (Reapproved 1996)
Standard Test Methods for
the Determination of the Modulus and Damping Properties
of Soils Using the Cyclic Triaxial Apparatus
This standard is issued under the fixed designation D 3999; 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 1.6.2 A 90° change in the direction of the major principal
stress occurs during the two halves of the loading cycle on
1.1 These test methods cover the determination of the
isotropically confined specimens and at certain levels of cyclic
modulus and damping properties of soils in either undisturbed
stress application on anisotropically confined specimens.
or reconstituted states by either load or stroke controlled cyclic
1.6.3 The maximum cyclic axial stress that can be applied to
triaxial techniques.
a saturated specimen is controlled by the stress conditions at
1.2 The cyclic triaxial properties of soil are evaluated
the end of confining stress application and the pore-water
relative to a number of factors including: strain level, density,
pressures generated during testing. For an isotropically con-
number of cycles, material type, saturation, and effective stress.
fined specimen tested in cyclic compression, the maximum
1.3 These test methods are applicable to both fine-grained
cyclic axial stress that can be applied to the specimen is equal
and coarse-grained soils as defined by the unified soil classi-
to the effective confining pressure. Since cohesionless soils are
fication system or by Classification D 2487. Test specimens
not capable of taking tension, cyclic axial stresses greater than
may be undisturbed or reconstituted by compaction in the
this value tend to lift the top platen from the soil specimen.
laboratory.
Also, as the pore-water pressure increases during tests per-
1.4 Two test methods are provided for using a cyclic loader
formed on isotropically confined specimens, the effective
to determine Young’s modulus (E) and damping (D) properties.
confining pressure is reduced, contributing to the tendency of
The first test method (A) permits the determination of E and D
the specimen to neck during the extension portion of the load
using a constant load apparatus. The second test method (B)
cycle, invalidating test results beyond that point.
permits the determination of E and D using a constant stroke
1.6.4 While it is advised that the best possible undisturbed
apparatus. The test methods are as follows:
specimens be obtained for cyclic testing, it is sometimes
1.4.1 Test Method A—This test method requires the appli-
necessary to reconstitute soil specimens. It has been shown that
cation of a constant cyclic load to the test specimen. It is used
different methods of reconstituting specimens to the same
for determining the Young’s modulus and damping under a
density may result in significantly different cyclic behavior.
constant load condition.
Also, undisturbed specimens will almost always be stronger
1.4.2 Test Method B—This test method requires the appli-
than reconstituted specimens of the same density.
cation of a constant cyclic deformation to the test specimen. It
1.6.5 The interaction between the specimen, membrane, and
is used for determining the Young’s modulus and damping
confining fluid has an influence on cyclic behavior. Membrane
under a constant stroke condition.
compliance effects cannot be readily accounted for in the test
1.5 The development of relationships to aid in interpreting
procedure or in interpretation of test results. Changes in
and evaluating test results are left to the engineer or office
pore-water pressure can cause changes in membrane penetra-
requesting the test.
tion in specimens of cohesionless soils. These changes can
1.6 Limitations—There are certain limitations inherent in
significantly influence the test results.
using cyclic triaxial tests to simulate the stress and strain
1.6.6 Despite these limitations, with due consideration for
conditions of a soil element in the field during an earthquake.
the factors affecting test results, carefully conducted cyclic
1.6.1 Nonuniform stress conditions within the test specimen
triaxial tests can provide data on the cyclic behavior of soils
are imposed by the specimen end platens.
with a degree of accuracy adequate for meaningful evaluations
of modulus and damping below a shearing strain level of
These test methods are under the jurisdiction of ASTM Committee D-18 on 0.5 %.
Soil and Rock and are the direct responsibility of Subcommittee D18.09 on
Dynamic Properties of Soils.
Current edition approved August 15, 1991. Published October 1991.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
D 3999 – 91 (1996)
1.7 The values stated in either SI or inch-pound units shall 3.2.5 effective force, (F)—the force transmitted through a
be regarded separately as standard. The values in each system soil or rock mass by intergranular pressures.
may not be exact equivalents, therefore, each system must be 3.2.6 hysteresis loop—a trace of load versus deformation
used independently of the other, without combining values in resulting from the application of one complete cycle of either
any way. a cyclic load or deformation. The area within the resulting loop
1.8 This standard does not purport to address all of the is due to energy dissipated by the specimen and apparatus, see
safety concerns, if any, associated with its use. It is the Fig. 1.
responsibility of the user of this standard to establish appro- 3.2.7 load duration—the time interval the specimen is
priate safety and health practices and determine the applica- subjected to a cyclic deviator stress.
bility of regulatory limitations prior to use. 3.2.8 principal stress—the stress normal to one of three
mutually perpendicular planes on which the shear stresses at a
2. Referenced Documents point in a body are zero.
−2
3.2.9 Young’s modulus (modulus of elasticity) [FL ]—the
2.1 ASTM Standards:
ratio of stress to strain for a material under given loading
D 422 Test Method for Particle-Size Analysis of Soils
conditions; numerically equal to the slope of the tangent or the
D 653 Terminology Relating to Soil, Rock, and Contained
secant of a stress-strain curve (same as Terminology D 653).
Fluids
D 854 Test Method for Specific Gravity of Soils
4. Summary of Test Method
D 1587 Practice for Thin-Walled Tube Sampling of Soils
4.1 The cyclic triaxial test consists of imposing either a
D 2216 Test Method for Laboratory Determination of Water
cyclic axial deviator stress of fixed magnitude (load control) or
(Moisture) Content of Soil and Rock
cyclic axial deformation (stroke control) on a cylindrical soil
D 2435 Test Method for One-Dimensional Consolidation
specimen enclosed in a triaxial pressure cell. The resulting
Properties of Soils
axial strain and axial stress are measured and used to calculate
D 2487 Classification of Soils for Engineering Purposes
either stress-dependent or stroke-dependent modulus and
(Unified Soil Classification System)
damping.
D 2488 Practice for Description and Identification of Soils
(Visual-Manual Procedure)
5. Significance and Use
D 3740 Practice for Minimum Requirements for Agencies
5.1 The cyclic triaxial modulus and damping test provides
Engaged in the Testing and/or Inspection of Soil and Rock
parameters that may be considered for use in dynamic, linear
as Used in Engineering Design and Construction
and non-linear analytical methods. These test methods are used
D 4220 Practice for Preserving and Transporting Soil
for the performance evaluation of both natural and engineered
Samples
structures under dynamic of cyclic loads such as caused by
D 4318 Test Method for Liquid Limit, Plastic Limit, and
earthquakes, ocean wave, or blast.
Plasticity Index of Soils
5.2 One of the primary purposes of these test methods is to
D 4767 Test Method for Consolidated-Undrained Triaxial
obtain data that are used to calculate Young’s modulus.
Compression Test on Cohesive Soils
2.2 USBR Standard:
NOTE 1—The quality of the result produced by this standard is
USBR 5210 Practice for Preparing Compacted Soil Speci-
dependent on the competence of the personnel performing it, and the
mens for Laboratory Use
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
3. Terminology
cautioned that compliance with Practice D 3740 does not in itself assure
3.1 Definitions:
3.1.1 The definitions of terms used in these test methods
shall be in accordance with Terminology D 653.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 back pressure—a pressure applied to the specimen
pore-water to cause air in the pore space to pass into solution
in the pore-water, that is, to saturate the specimen.
3.2.2 cycle duration—the time interval between successive
applications of a deviator stress.
−2
3.2.3 deviator stress [FL ]—the difference between the
major and minor principal stresses in a triaxial test.
3.2.4 effective confining stress—the confining pressure (the
difference between the cell pressure and the pore-water pres-
sure) prior to shearing the specimen.
FIG. 1 Schematic of Typical Hysteresis Loop Generated by Cyclic
Annual Book of ASTM Standards, Vol 04.08.
Available from U.S. Department of the Interior, Bureau of Reclamation. Triaxial Apparatus
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
D 3999 – 91 (1996)
reliable results. Reliable results depend on many factors; Practice D 3740
provides a means of evaluating some of those factors.
6. Apparatus
6.1 General—In many ways, triaxial equipment suitable for
cyclic triaxial modulus and damping tests is similar to equip-
ment used for the consolidated-undrained triaxial compression
test (see Test Method D 4767). However, there are special
features described in the following sections that are required to
perform acceptable cyclic triaxial tests. A schematic represen-
tation of the various components comprising a typical triaxial
modulus and damping test setup is shown in Fig. 2.
6.2 Triaxial Pressure Cell—The primary considerations in
selecting the cell are tolerances for the piston, top platen, and
low friction piston seal, Fig. 3.
6.2.1 Two linear ball bushings or similar bearings should be
used to guide the load rod to minimize friction and to maintain
alignment.
6.2.2 The load rod diameter should be large enough to
minimize lateral bending. A minimum load rod diameter of ⁄6
the specimen diameter has been used successfully in many
laboratories.
6.2.3 The load rod seal is a critical element in triaxial cell
design for cyclic soils testing if an external load cell connected
to the loading rod is employed. The seal must exert negligible
friction on the load rod. The maximum acceptable piston
FIG. 3 Typical Cyclic Triaxial Pressure Cell
friction tolerable without applying load corrections is com-
monly considered to be 62 % of the maximum single ampli-
tude cyclic load applied in the test, refer to Fig. 4. The use of
FIG. 2 Schematic Representation of Load or Stroke-Controlled Cyclic Triaxial Test Setup
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
D 3999 – 91 (1996)
1 1
NOTE 1—Frequency = ⁄PERIOD = ⁄T .
FIG. 4 Definitions Related to Cyclic Loading
a seal described in 9.1 and described by Ladd and Dutko , and
Chan will meet these requirements.
6.2.4 Top and bottom platen alignment is critical to avoid
increasing a nonuniform state of stress in the specimen.
Internal tie-rod triaxial cells have worked well at a number of
laboratories. These cells allow the placement of the cell wall
after the specimen is in place between the loading platens.
Acceptable limits on platen eccentricity and parallelism are
shown in Fig. 5.
FIG. 5 Limits on Acceptable Platen and Load Rod Alignment: (a)
eccentricity, (b) parallelism, (c) eccentricity between Top Platen
6.2.5 Since axial loading in cyclic triaxial tests is in exten-
and Sample
sion as well as in compression, the load rod shall be rigidly
connected to the top platen by a method such as one of those
shown in Fig. 6.
specimen as it deforms. The type of apparatus typically
6.2.6 There shall be provision for specimen drainage at both
employed can range from a simple cam to a closed loop
the top and bottom platens.
electro-hydraulic system.
6.3 Cyclic Loading Equipment:
6.4 Recording Equipment:
6.3.1 Cyclic loading equipment used for load controlled
6.4.1 Load, displacement, and pore water pressure transduc-
cyclic triaxial tests must be capable of applying a uniform
ers are required to monitor specimen behavior during cyclic
sinusoidal load at a frequency within the range of 0.1 to 2 Hz.
loading; provisions for monitoring the chamber pressure during
The loading device must be able to maintain uniform cyclic
cyclic loading are optional.
loadings to at least 0.5 % double amplitude stress, refer to Fig.
6.4.2 Load Measurement—Generally, the load cell capacity
4. Unsymmetrical compression-extension load peaks, nonuni-
should be no greater than five times the total maximum load
formity of pulse duration, “ringing”, or load fall-off at large
applied to the test specimen to ensure that the necessary
strains must not exceed tolerances illustrated in Fig. 7. The
measurement accuracy is achieved. The minimum performance
equipment must also be able to apply the cyclic load about an
characteristics of the load cell are presented in Table 1.
initial static load on the loading rod.
6.4.3 Axial Deformation Measurement—Displacement
6.3.2 Cyclic loading equipment used for deformation-
measuring devices such as linear variable differential trans-
controlled cyclic triaxial tests must be capable of applying a
former (LVDT), Potentiometer-type deformation transducers,
uniform sinusoidal deformation at a frequency range of 0.1 to
and eddy current sensors may be used if they meet the required
2 Hz. The equipment must also b
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