ASTM D4767-11(2020)
(Test Method)Standard Test Method for Consolidated Undrained Triaxial Compression Test for Cohesive Soils
Standard Test Method for Consolidated Undrained Triaxial Compression Test for Cohesive Soils
SIGNIFICANCE AND USE
4.1 The shear strength of a saturated soil in triaxial compression depends on the stresses applied, time of consolidation, strain rate, and the stress history experienced by the soil.
4.2 In this test method, the shear characteristics are measured under undrained conditions and is applicable to field conditions where soils that have been fully consolidated under one set of stresses are subjected to a change in stress without time for further consolidation to take place (undrained condition), and the field stress conditions are similar to those in the test method.
Note 1: If the strength is required for the case where the soil is not consolidated during testing prior to shear, refer to Test Method D2850 or Test Method D2166/D2166M.
4.3 Using the pore-water pressure measured during the test, the shear strength determined from this test method can be expressed in terms of effective stress. This shear strength may be applied to field conditions where full drainage can occur (drained conditions) or where pore pressures induced by loading can be estimated, and the field stress conditions are similar to those in the test method.
4.4 The shear strength determined from the test expressed in terms of total stresses (undrained conditions) or effective stresses (drained conditions) is commonly used in embankment stability analyses, earth pressure calculations, and foundation design.
Note 2: Notwithstanding the statements on precision and bias contained in this test method. The precision of this test method is dependent on the competence of the personnel performing it and the suitability of the equipment and facilities used. Agencies which meet the criteria of Practice D3740 are generally considered capable of competent testing. Users of this test method are cautioned that compliance with Practice D3740 does not ensure reliable testing. Reliable testing depends on several factors; Practice D3740 provides a means of evaluating some of those factors.
SCOPE
1.1 This test method covers the determination of strength and stress-strain relationships of a cylindrical specimen of either an intact, reconstituted, or remolded saturated cohesive soil. Specimens are isotropically consolidated and sheared in compression without drainage at a constant rate of axial deformation (strain controlled).
1.2 This test method provides for the calculation of total and effective stresses, and axial compression by measurement of axial load, axial deformation, and pore-water pressure.
1.3 This test method provides data useful in determining strength and deformation properties of cohesive soils such as Mohr strength envelopes and Young's modulus. Generally, three specimens are tested at different effective consolidation stresses to define a strength envelope.
1.4 The determination of strength envelopes and the development of relationships to aid in interpreting and evaluating test results are beyond the scope of this test method and must be performed by a qualified, experienced professional.
1.5 All observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice D6026.
1.5.1 The methods used to specify how data are collected, calculated, or recorded in this standard are regarded as the industry standard. In addition, they are representative of the significant digits that generally should be retained. The procedures used do not consider material variation, purpose for obtaining the data, special purpose studies or any consideration of end use. It is beyond the scope of this test method to consider significant digits used in analysis methods for engineering design.
1.6 Units—The values stated in SI units are to be regarded as standard. The values given in parentheses are provided for information only and are not considered standard. Reporting of test results in units other than SI shall not be regarded as nonconformance with this test method.
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Standards Content (Sample)
This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D4767 − 11 (Reapproved 2020)
Standard Test Method for
Consolidated Undrained Triaxial Compression Test for
Cohesive Soils
This standard is issued under the fixed designation D4767; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope test results in units other than SI shall not be regarded as
nonconformance with this test method.
1.1 This test method covers the determination of strength
1.6.1 The gravitational system of inch-pound units is used
and stress-strain relationships of a cylindrical specimen of
when dealing with inch-pound units. In this system, the pound
either an intact, reconstituted, or remolded saturated cohesive
(lbf)representsaunitofforce(weight),whiletheunitformass
soil. Specimens are isotropically consolidated and sheared in
is slugs. The slug unit is not given, unless dynamic (F = ma)
compression without drainage at a constant rate of axial
calculations are involved.
deformation (strain controlled).
1.6.2 It is common practice in the engineering/construction
1.2 Thistestmethodprovidesforthecalculationoftotaland
profession to concurrently use pounds to represent both a unit
effective stresses, and axial compression by measurement of
of mass (lbm) and of force (lbf). This implicitly combines two
axial load, axial deformation, and pore-water pressure.
separate systems of units; that is, the absolute system and the
gravitational system. It is scientifically undesirable to combine
1.3 This test method provides data useful in determining
strength and deformation properties of cohesive soils such as the use of two separate sets of inch-pound units within a single
standard. As stated, this standard includes the gravitational
Mohr strength envelopes and Young’s modulus. Generally,
three specimens are tested at different effective consolidation system of inch-pound units and does not use/present the slug
unitformass.However,theuseofbalancesorscalesrecording
stresses to define a strength envelope.
pounds of mass (lbm) or recording density in lbm/ft shall not
1.4 The determination of strength envelopes and the devel-
be regarded as nonconformance with this standard.
opment of relationships to aid in interpreting and evaluating
1.6.3 The terms density and unit weight are often used
test results are beyond the scope of this test method and must
interchangeably. Density is mass per unit volume whereas unit
be performed by a qualified, experienced professional.
weight is force per unit volume. In this standard density is
1.5 All observed and calculated values shall conform to the
given only in SI units. After the density has been determined,
guidelines for significant digits and rounding established in
the unit weight is calculated in SI or inch-pound units, or both.
Practice D6026.
1.7 This standard does not purport to address all of the
1.5.1 The methods used to specify how data are collected,
safety concerns, if any, associated with its use. It is the
calculated, or recorded in this standard are regarded as the
responsibility of the user of this standard to establish appro-
industry standard. In addition, they are representative of the
priate safety, health, and environmental practices and deter-
significant digits that generally should be retained. The proce-
mine the applicability of regulatory limitations prior to use.
dures used do not consider material variation, purpose for
1.8 This international standard was developed in accor-
obtainingthedata,specialpurposestudiesoranyconsideration
dance with internationally recognized principles on standard-
of end use. It is beyond the scope of this test method to
ization established in the Decision on Principles for the
consider significant digits used in analysis methods for engi-
Development of International Standards, Guides and Recom-
neering design.
mendations issued by the World Trade Organization Technical
1.6 Units—The values stated in SI units are to be regarded
Barriers to Trade (TBT) Committee.
as standard. The values given in parentheses are provided for
informationonlyandarenotconsideredstandard.Reportingof
2. Referenced Documents
2.1 ASTM Standards:
ThistestmethodisunderthejurisdictionofASTMCommitteeD18onSoiland
Rock and is the direct responsibility of Subcommittee D18.05 on Strength and
Compressibility of Soils. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved April 1, 2020. Published April 2020. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1988. Last previous edition approved in 2011 as D4767–11. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/D4767-11R20. the ASTM website.
*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
D4767 − 11 (2020)
D422Test Method for Particle-SizeAnalysis of Soils (With- 4.2 In this test method, the shear characteristics are mea-
drawn 2016) sured under undrained conditions and is applicable to field
D653Terminology Relating to Soil, Rock, and Contained conditions where soils that have been fully consolidated under
Fluids one set of stresses are subjected to a change in stress without
D854Test Methods for Specific Gravity of Soil Solids by time for further consolidation to take place (undrained
Water Pycnometer condition),andthefieldstressconditionsaresimilartothosein
D1587/D1587MPractice forThin-WalledTube Sampling of the test method.
Fine-Grained Soils for Geotechnical Purposes
NOTE 1—If the strength is required for the case where the soil is not
D2166/D2166MTest Method for Unconfined Compressive
consolidated during testing prior to shear, refer to Test Method D2850 or
Strength of Cohesive Soil Test Method D2166/D2166M.
D2216Test Methods for Laboratory Determination ofWater
4.3 Using the pore-water pressure measured during the test,
(Moisture) Content of Soil and Rock by Mass
the shear strength determined from this test method can be
D2435/D2435MTest Methods for One-Dimensional Con-
expressed in terms of effective stress. This shear strength may
solidation Properties of Soils Using Incremental Loading
be applied to field conditions where full drainage can occur
D2850Test Method for Unconsolidated-Undrained Triaxial
(drained conditions) or where pore pressures induced by
Compression Test on Cohesive Soils
loading can be estimated, and the field stress conditions are
D3740Practice for Minimum Requirements for Agencies
similar to those in the test method.
Engaged in Testing and/or Inspection of Soil and Rock as
4.4 Theshearstrengthdeterminedfromthetestexpressedin
Used in Engineering Design and Construction
terms of total stresses (undrained conditions) or effective
D4220/D4220MPractices for Preserving and Transporting
stresses(drainedconditions)iscommonlyusedinembankment
Soil Samples
stability analyses, earth pressure calculations, and foundation
D4318Test Methods for Liquid Limit, Plastic Limit, and
design.
Plasticity Index of Soils
D4753Guide for Evaluating, Selecting, and Specifying Bal- NOTE 2—Notwithstanding the statements on precision and bias con-
tained in this test method. The precision of this test method is dependent
ances and Standard Masses for Use in Soil, Rock, and
onthecompetenceofthepersonnelperformingitandthesuitabilityofthe
Construction Materials Testing
equipmentandfacilitiesused.AgencieswhichmeetthecriteriaofPractice
D6026Practice for Using Significant Digits in Geotechnical
D3740 are generally considered capable of competent testing. Users of
Data
this test method are cautioned that compliance with Practice D3740 does
not ensure reliable testing. Reliable testing depends on several factors;
3. Terminology
Practice D3740 provides a means of evaluating some of those factors.
3.1 Definitions—For standard definitions of common tech-
5. Apparatus
nical terms, refer to Terminology D653.
5.1 The requirements for equipment needed to perform
3.2 Definitions of Terms Specific to This Standard:
satisfactory tests are given in the following sections. See Fig.
3.2.1 back pressure—a pressure applied to the specimen
1 and Fig. 2
pore-water to cause air in the pore space to compress and to
5.2 Axial Loading Device—The axial loading device shall
pass into solution in the pore-water thereby increasing the
be a screw jack driven by an electric motor through a geared
percent saturation of the specimen.
transmission, a hydraulic loading device, or any other com-
3.2.2 effective consolidation stress—the difference between
pression device with sufficient capacity and control to provide
the cell pressure and the pore-water pressure prior to shearing
therateofaxialstrain(loading)prescribedin8.4.2.Therateof
the specimen.
advance of the loading device shall not deviate by more than
61% from the selected value. Vibration due to the operation
3.2.3 failure—a maximum-stress condition or stress at a
of the loading device shall be sufficiently small to not cause
defined strain for a test specimen. Failure is often taken to
dimensional changes in the specimen or to produce changes in
correspond to the maximum principal stress difference (maxi-
pore-water pressure when the drainage valves are closed.
mum deviator stress) attained or the principal stress difference
(deviatorstress)at15%axialstrain,whicheverisobtainedfirst
NOTE 3—Aloading device may be judged to produce sufficiently small
during the performance of a test. Depending on soil behavior
vibrations if there are no visible ripples in a glass of water placed on the
and field application, other suitable failure criteria may be loading platform when the device is operating at the speed at which the
test is performed.
defined, such as maximum effective stress obliquity, (σ '/
σ ') , or the principal stress difference (deviator stress) at a 5.3 Axial Load-Measuring Device—The axial load-
3 max
selected axial strain other than 15%. measuring device shall be an electronic load cell, hydraulic
load cell, or any other load-measuring device capable of the
4. Significance and Use
accuracy prescribed in this paragraph and may be a part of the
4.1 The shear strength of a saturated soil in triaxial com- axial loading device. The axial load-measuring device shall be
pressiondependsonthestressesapplied,timeofconsolidation, capable of measuring the axial load to an accuracy of within
strain rate, and the stress history experienced by the soil. 1% of the axial load at failure. If the load-measuring device is
located inside the triaxial compression chamber, it shall be
insensitive to horizontal forces and to the magnitude of the
The last approved version of this historical standard is referenced on
www.astm.org. chamber pressure.
D4767 − 11 (2020)
FIG. 1 Schematic Diagram of a Typical Consolidated Undrained Triaxial Apparatus
FIG. 2 Filter Strip Cage
5.4 Triaxial Compression Chamber—The triaxial chamber specimen base and to the cap to allow saturation and drainage
shall have a working chamber pressure equal to the sum of the of the specimen when required. The chamber shall provide a
effective consolidation stress and the back pressure. It shall connection to the cap.
consist of a top plate and a base plate separated by a cylinder.
5.5 Axial Load Piston—The piston passing through the top
The cylinder may be constructed of any material capable of
of the chamber and its seal must be designed so the variation
withstanding the applied pressures. It is desirable to use a
in axial load due to friction does not exceed 0.1% of the axial
transparent material or have a cylinder provided with viewing
load at failure and so there is negligible lateral bending of the
portssothebehaviorofthespecimenmaybeobserved.Thetop
piston during loading.
plate shall have a vent valve such that air can be forced out of
the chamber as it is filled. The baseplate shall have an inlet
NOTE 4—The use of two linear ball bushings to guide the piston is
through which to fill the chamber, and inlets leading to the recommended to minimize friction and maintain alignment.
D4767 − 11 (2020)
NOTE 5—Aminimum piston diameter of ⁄6 the specimen diameter has pressure, and record the volume change.
been used successfully in many laboratories to minimize lateral bending.
5.9 Volume Change Measurement Device—The volume of
5.6 Pressure and Vacuum-Control Devices—The chamber
water entering or leaving the specimen shall be measured with
pressure and back pressure control devices shall be capable of
an accuracy of within 60.05% of the total volume of the
applying and controlling pressures to within 62 kPa (0.25
specimen. The volume measuring device is usually a burette
lb/in. ) for effective consolidation pressures less than 200 kPa
connected to the back pressure but may be any other device
(28 lbf/in. ) and to within 61% for effective consolidation
meeting the accuracy requirement. The device must be able to
pressures greater than 200 kPa. The vacuum-control device
withstand the maximum back pressure.
shallbecapableofapplyingandcontrollingpartialvacuumsto
5.10 Deformation Indicator—The vertical deformation of
within 62 kPa. The devices shall consist of pressure/volume
thespecimenisusuallydeterminedfromthetravelofthepiston
controllers pneumatic pressure regulators, combination pneu-
acting on the top of the specimen. The piston travel shall be
matic pressure and vacuum regulators, or any other device
capable of applying and controlling pressures or partial vacu- measured with an accuracy of at least 0.25% of the initial
specimen height. The deformation indicator shall have a range
ums to the required tolerances. These tests can require a test
duration of several day. Therefore, an air/water interface is not of at least 15% of the initial height of the specimen and may
be a dial indicator or other measuring device meeting the
recommended for either the chamber pressure or back pressure
systems, unless isolated from the specimen and chamber (for requirements for accuracy and range.
example, by long tubing).
5.11 Specimen Cap and Base—The specimen cap and base
5.7 Pressure- and Vacuum-Measurement Devices—The
shall be designed to provide drainage from both ends of the
chamber pressure-, back pressure-, and vacuum-measuring
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