ASTM D2435/D2435M-11(2020)
(Test Method)Standard Test Methods for One-Dimensional Consolidation Properties of Soils Using Incremental Loading
Standard Test Methods for One-Dimensional Consolidation Properties of Soils Using Incremental Loading
SIGNIFICANCE AND USE
5.1 The data from the consolidation test are used to estimate the magnitude and rate of both differential and total settlement of a structure or earthfill. Estimates of this type are of key importance in the design of engineered structures and the evaluation of their performance.
5.2 The test results can be greatly affected by sample disturbance. Careful selection and preparation of test specimens is required to reduce the potential of disturbance effects.
Note 3: Notwithstanding the statement on precision and bias contained in this standard, the precision of this test method is dependent on the competence of the personnel performing the test and suitability of the equipment and facilities used. Agencies that meet the criteria of Practice D3740 generally are considered capable of competent and objective testing. Users of this test method are cautioned that compliance with Practice D3740 does not assure reliable testing. Reliable testing depends on many factors, and Practice D3740 provides a means of evaluation some of these factors.
5.3 Consolidation test results are dependent on the magnitude of the load increments. Traditionally, the axial stress is doubled for each increment resulting in a load increment ratio of 1. For intact samples, this loading procedure has provided data from which estimates of the preconsolidation stress, using established interpretation techniques, compare favorably with field observations. Other loading schedules may be used to model particular field conditions or meet special requirements. For example, it may be desirable to inundate and load the specimen in accordance with the wetting or loading pattern expected in the field in order to best evaluate the response. Load increment ratios of less than 1 may be desirable for soils that are highly sensitive or whose response is highly dependent on strain rate.
5.4 The interpretation method specified by these test methods to estimate the preconsolidation stress provides a simple te...
SCOPE
1.1 These test methods cover procedures for determining the magnitude and rate of consolidation of soil when it is restrained laterally and drained axially while subjected to incrementally applied controlled-stress loading. Two alternative procedures are provided as follows:
1.1.1 Test Method A—This test method is performed with constant load increment duration of 24 h, or multiples thereof. Time-deformation readings are required on a minimum of two load increments. This test method provides only the compression curve of the specimen and the results combine both primary consolidation and secondary compression deformations.
1.1.2 Test Method B—Time-deformation readings are required on all load increments. Successive load increments are applied after 100 % primary consolidation is reached, or at constant time increments as described in Test Method A. This test method provides the compression curve with explicit data to account for secondary compression, the coefficient of consolidation for saturated materials, and the rate of secondary compression.
Note 1: The determination of the rate and magnitude of consolidation of soil when it is subjected to controlled-strain loading is covered by Test Method D4186/D4186M.
1.2 These test methods are most commonly performed on saturated intact samples of fine grained soils naturally sedimented in water, however, the basic test procedure is applicable, as well, to specimens of compacted soils and intact samples of soils formed by other processes such as weathering or chemical alteration. Evaluation techniques specified in these test methods assume the pore space is fully saturated and are generally applicable to soils naturally sedimented in water. Tests performed on other unsaturated materials such as compacted and residual (weathered or chemically altered) soils may require special evaluation techniques. In particular, the rate of consolidation (interpretation of the time ...
General Information
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: D2435/D2435M − 11 (Reapproved 2020)
Standard Test Methods for
One-Dimensional Consolidation Properties of Soils Using
1
Incremental Loading
This standard is issued under the fixed designation D2435/D2435M; 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 rate of consolidation (interpretation of the time curves) is only
applicable to fully saturated specimens.
1.1 These test methods cover procedures for determining
the magnitude and rate of consolidation of soil when it is
1.3 It shall be the responsibility of the agency requesting
restrained laterally and drained axially while subjected to
this test to specify the magnitude and sequence of each load
incrementally applied controlled-stress loading. Two alterna-
increment, including the location of a rebound cycle, if
tive procedures are provided as follows:
required, and, for Test Method A, the load increments for
1.1.1 Test Method A—This test method is performed with
which time-deformation readings are desired. The required
constant load increment duration of 24 h, or multiples thereof.
maximum stress level depends on the purpose of the test and
Time-deformation readings are required on a minimum of two
must be agreed on with the requesting agency. In the absence
load increments. This test method provides only the compres-
of specific instructions, Section 11 provides the default load
sion curve of the specimen and the results combine both
increment and load duration schedule for a standard test.
primary consolidation and secondary compression deforma-
tions. NOTE 2—Time-deformation readings are required to determine the time
for completion of primary consolidation and for evaluating the coefficient
1.1.2 Test Method B—Time-deformation readings are re-
of consolidation, c . Since c varies with stress level and loading type
v v
quired on all load increments. Successive load increments are
(loading or unloading), the load increments with timed readings must be
applied after 100 % primary consolidation is reached, or at
selected with specific reference to the individual project.Alternatively, the
constant time increments as described in Test Method A. This
requesting agency may specify Test Method B wherein the time-
test method provides the compression curve with explicit data
deformation readings are taken on all load increments.
to account for secondary compression, the coefficient of
1.4 These test methods do not address the use of a back
consolidation for saturated materials, and the rate of secondary
pressure to saturate the specimen. Equipment is available to
compression.
perform consolidation tests using back pressure saturation.The
NOTE 1—The determination of the rate and magnitude of consolidation
addition of back pressure saturation does not constitute non-
of soil when it is subjected to controlled-strain loading is covered by Test
conformance to these test methods.
Method D4186/D4186M.
1.5 Units—The values stated in either SI units or inch-
1.2 These test methods are most commonly performed on
pound units [given in brackets] are to be regarded separately as
saturated intact samples of fine grained soils naturally sedi-
standard. The values stated in each system may not be exact
mented in water, however, the basic test procedure is
equivalents;therefore,eachsystemshallbeusedindependently
applicable, as well, to specimens of compacted soils and intact
of the other. Combining values from the two systems may
samples of soils formed by other processes such as weathering
result in non-conformance with the standard.
or chemical alteration. Evaluation techniques specified in these
test methods assume the pore space is fully saturated and are
1.5.1 In the engineering profession it is customary practice
generally applicable to soils naturally sedimented in water. touse,interchangeably,unitsrepresentingbothmassandforce,
Tests performed on other unsaturated materials such as com-
unless dynamic calculations (F = Ma) are involved. This im-
pacted and residual (weathered or chemically altered) soils
plicitly combines two separate systems of units, that is, the
may require special evaluation techniques. In particular, the
absolute system and the gravimetric system. It is scientifically
undesirable to combine two separate systems within a single
standard. This test method has been written using SI units;
1 however, inch-pound conversions are given in the gravimetric
These test methods
...
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