ASTM D2435/D2435M-11(2020)

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
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 are under the jurisdiction ofASTM Committee D18 on Soil
and Rock and is the direct responsibility of Subcommittee D18.05 on Strength and
system, where the pound (lbf) represents a unit of force
Compressibility of Soils.
(weight). The use of balances or scales recording pounds of
Current edition approved April 1, 2020. Published April 2020. Originally
mass (lbm), or the recording of density in lb/ft should not be
approved in 1965. Last previous edition approved in 2011 as D2435–11. DOI:
10.1520/D2435_D2435M-11R20. regarded as nonconformance with this test method.
*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
D2435/D2435M − 11 (2020)
1.6 Observed and calculated values shall conform to the D4753 Guide for Evaluating, Selecting, and Specifying Bal-
guidelines for significant digits and rounding established in ances and Standard Masses for Use in Soil, Rock, and
Practice D6026, unless superseded by this test method. Construction Materials Testing
1.6.1 The method used to specify how data are collected, D6026 Practice for Using Significant Digits in Geotechnical
calculated, or recorded in this standard is not directly related to Data
theaccuracytowhichthedatacanbeappliedindesignorother D6027/D6027M Practice for Calibrating Linear Displace-
uses, or both. How one applies the results obtained using this ment Transducers for Geotechnical Purposes
standard is beyond its scope.
3. Terminology
1.7 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
3.1 For definitions of technical terms used in these test
responsibility of the user of this standard to establish appro-
methods, see Terminology D653.
priate safety, health, and environmental practices and deter-
3.2 Definitions of Terms Specific to This Standard:
mine the applicability of regulatory limitations prior to use.
3.2.1 axial deformation (L, L, %, or -), n—the change in
1.8 This international standard was developed in accor-
axial dimension of the specimen which can be expressed in
dance with internationally recognized principles on standard-
terms of length, height of specimen, strain or void ratio.
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom- 3.2.2 estimated preconsolidation stress (F/L ), n—the value
mendations issued by the World Trade Organization Technical of the preconsolidation stress determined by the technique
Barriers to Trade (TBT) Committee. prescribed in these test methods for the purpose of aiding the
laboratory in the performance of the test. This estimation
should not be considered equivalent to an engineering inter-
2. Referenced Documents
2 pretation of the test measurements.
2.1 ASTM Standards:
3.2.3 load (F), n—in the context of soil testing, the act of
D422 Test Method for Particle-SizeAnalysis of Soils (With-
drawn 2016) applying force or deformation to the boundary of a test
specimen.Intheincrementalconsolidationtestthisisgenerally
D653 Terminology Relating to Soil, Rock, and Contained
Fluids performed using weights on a hanger.
D854 Test Methods for Specific Gravity of Soil Solids by
3.2.4 load increment, n—one individual step of the test
Water Pycnometer
duringwhichthespecimenisunderaconstanttotalaxialstress.
D1587/D1587M Practice for Thin-Walled Tube Sampling of
3.2.5 load increment duration (T), n—thelengthoftimethat
Fine-Grained Soils for Geotechnical Purposes
one value of total axial stress is maintained on the specimen.
D2216 Test Methods for Laboratory Determination of Water
(Moisture) Content of Soil and Rock by Mass 3.2.6 load increment ratio, LIR (-), n—the change (increase
or decrease) in total axial stress to be applied to the specimen
D2487 Practice for Classification of Soils for Engineering
Purposes (Unified Soil Classification System) in a single step divided by the current total axial stress.
D2488 Practice for Description and Identification of Soils 3.2.6.1 Discussion—Load Increment Ratio is historically
(Visual-Manual Procedures)
used in consolidation testing to reflect the fact that the test was
D3550/D3550M Practice for Thick Wall, Ring-Lined, Split performed by adding weights to apply the total axial stress to
Barrel, Drive Sampling of Soils
the specimen.
D3740 Practice for Minimum Requirements for Agencies 2
3.2.7 total axial stress (F/L ), n—the force acting on the
Engaged in Testing and/or Inspection of Soil and Rock as
specimen divided by the specimen area. Once consolidation is
Used in Engineering Design and Construction
complete, the effective axial stress is assumed to equal the total
D4186/D4186M TestMethodforOne-DimensionalConsoli-
axial stress.
dation Properties of Saturated Cohesive Soils Using
3.2.8 total axial stress increment (F/L ), n—the change
Controlled-Strain Loading
(increase or decrease) in total axial stress applied in one single
D4220/D4220M Practices for Preserving and Transporting
step. The change may be an increase or a decrease in stress.
Soil Samples
D4318 Test Methods for Liquid Limit, Plastic Limit, and
4. Summary of Test Methods
Plasticity Index of Soils
D4452 Practice for X-Ray Radiography of Soil Samples
4.1 In these test methods a soil specimen is restrained
D4546 Test Methods for One-Dimensional Swell or Col-
laterally and loaded axially with total stress increments. Each
lapse of Soils
stress increment is maintained until excess pore water pres-
sures are essentially dissipated. Pore pressure is assumed to be
dissipated based on interpretation of the time deformation
underconstanttotalstress.Thisinterpretationisfoundedonthe
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
assumption that the soil is 100% saturated. Measurements are
Standards volume information, refer to the standard’s Document Summary page on
made of change in the specimen height and these data are used
the ASTM website.
to determine the relationship between the effective axial stress
The last approved version of this historical standard is referenced on
www.astm.org. and void ratio or strain. When time deformation readings are
D2435/D2435M − 11 (2020)
taken throughout an increment, the rate of consolidation is 5.6 The apparatus in general use for these test methods do
evaluated with the coefficient of consolidation. not have provisions for verification of saturation. Most intact
samples taken from below the water table will be saturated.
5. Significance and Use However, the time rate of deformation is very sensitive to
degree of saturation and caution must be exercised regarding
5.1 The data from the consolidation test are used to estimate
estimates for duration of settlements when partially saturated
the magnitude and rate of both differential and total settlement
conditions prevail. Inundation of the test specimen does not
of a structure or earthfill. Estimates of this type are of key
significantly change the degree of saturation of the test
importance in the design of engineered structures and the
specimen but rather provides boundary water to eliminate
evaluation of their performance.
negative pore pressure associated with sampling and prevents
evaporation during the test. The extent to which partial
5.2 The test results can be greatly affected by sample
saturation influences the test results may be a part of the test
disturbance. Careful selection and preparation of test speci-
evaluation and may include application of theoretical models
mens is required to reduce the potential of disturbance effects.
other than conventional consolidation theory.Alternatively, the
NOTE 3—Notwithstanding the statement on precision and bias con-
test may be performed using an apparatus equipped to saturate
tained in this standard, the precision of this test method is dependent on
the specimen.
the competence of the personnel performing the test and suitability of the
equipment and facilities used. Agencies that meet the criteria of Practice
5.7 These test methods use conventional consolidation
D3740 generally are considered capable of competent and objective
theory based on Terzaghi’s consolidation equation to compute
testing. Users of this test method are cautioned that compliance with
the coefficient of consolidation, c . The analysis is based upon
v
Practice D3740 does not assure reliable testing. Reliable testing depends
the following assumptions:
onmanyfactors,andPracticeD3740providesameansofevaluationsome
of these factors.
5.7.1 The soil is saturated and has homogeneous properties;
5.7.2 The flow of pore water is in the vertical direction;
5.3 Consolidation test results are dependent on the magni-
5.7.3 The compressibility of soil particles and pore water is
tude of the load increments. Traditionally, the axial stress is
negligible compared to the compressibility of the soil skeleton;
doubled for each increment resulting in a load increment ratio
5.7.4 The stress-strain relationship is linear over the load
of 1. For intact samples, this loading procedure has provided
increment;
data from which estimates of the preconsolidation stress, using
5.7.5 The ratio of soil permeability to soil compressibility is
established interpretation techniques, compare favorably with
constant over the load increment; and
field observations. Other loading schedules may be used to
5.7.6 Darcy’s law for flow through porous media applies.
model particular field conditions or meet special requirements.
For example, it may be desirable to inundate and load the
6. Apparatus
specimen in accordance with the wetting or loading pattern
expected in the field in order to best evaluate the response.
6.1 Load Device—Asuitable device for applying axial loads
Load increment ratios of less than 1 may be desirable for soils
or total stresses to the specimen.The device shall be capable of
that are highly sensitive or whose response is highly dependent
maintaining the specified loads for long periods of time with a
on strain rate.
precision of 6 0.5 % of the applied load and shall permit quick
application of a given load increment without significant
5.4 The interpretation method specified by these test meth-
impact. Load application should be completed in a time
ods to estimate the preconsolidation stress provides a simple
corresponding to 0.01 times t or less.
technique to verify that one set of time readings are taken after 100
the preconsolidation stress and that the specimen is loaded to a
NOTE 4—As an example, for soils where primary consolidation is
sufficiently high stress level. Several other evaluation tech-
completed in 3 min, the applied load should be stable in less than 2 s.
niques exist and may yield different estimates of the precon-
6.2 Consolidometer—A device to hold the specimen in a
solidation stress.Alternative techniques to estimate the precon-
ring that is either fixed to the base or floating (supported by
solidation stress may be used when agreed to by the requesting
friction on the periphery of specimen) with porous disks on
agency and still be in conformance with these test methods.
each face of the specimen.The inside diameter of the ring shall
be fabricated to a tolerance of at least 0.1 % of the diameter.
5.5 Consolidation test results are dependent upon the dura-
The consolidometer shall also provide a means of submerging
tion of each load increment. Traditionally, the load duration is
the specimen in water, for transmitting the concentric axial
the same for each increment and equal to 24 h. For some soils,
load to the porous disks, and for measuring the axial deforma-
the rate of consolidation is such that complete consolidation
tion of specimen.
(dissipation of excess pore pressure) will require more than 24
6.2.1 Minimum Specimen Diameter—The minimum speci-
h. The apparatus in general use does not have provisions for
men diameter or inside diameter of the specimen ring shall be
formal verification of pore pressure dissipation. It is necessary
50 mm [2.0 in.].
to use an interpretation technique which indirectly determines
that consolidation is essentially complete. These test methods 6.2.2 Minimum Specimen Height—The minimum initial
specimen height shall be 12 mm [0.5 in.], but shall be not less
specify procedures for two techniques (Method A and Method
B), however alternative techniques may be used when agreed than ten times the maximum particle diameter.
to by the requesting agency and still be in conformance with 6.2.3 Minimum Specimen Diameter-to-Height Ratio—The
these test methods. minimum specimen diameter-to-height ratio shall be 2.5.
D2435/D2435M − 11 (2020)
NOTE 5—The use of greater diameter-to-height ratios is recommended.
the porous disk and the specimen.The screen must be included
To minimize the effects of friction between the periphery of the specimen
when evaluating the impedance factor. Monofilament-nylon
and the inside of the ring, a diameter-to-height ratio greater than four is
filter screen or hardened, low ash, grade 54 filter paper may be
preferable.
used for the filter screen material.
6.2.4 Specimen Ring Rigidity—The ring shall be stiff
NOTE10—Filtersshouldbecuttoapproximatelythesamedimensionas
enough to prevent significant lateral deformation of the speci-
the cross section of the test specimen. When following the wet setup
procedure, soak the filter paper, if used, in a container of water to allow it
men throughout the test. The rigidity of the ring shall be such
to equilibrate before testing.
that, under hydrostatic stress conditions in the specimen, the
6.5 Specimen Trimming Device—A trimming turntable or a
change in diameter of the ring will not exceed 0.04 % of the
cylindrical cutting ring may be used for trimming the sample
diameter under the greatest load applied.
down to the inside diameter of the consolidometer ring with
NOTE 6—For example, a ring thickness (for metallic rings) of 3.2 mm
minimal disturbance.Acutter having the same inside diameter
[ ⁄8 in.] will be adequate for stresses up to 6000 kPa [900 lbf/in ] for a
(or up to 0.05 mm larger) as the specimen ring shall attach to
specimen diameter of 63.5 mm [2.5 in.].
or be integral with the specimen ring. The cutter shall have a
6.2.5 Specimen Ring Material—The ring shall be made of a
sharp edge, a highly polished surface and be coated with a
materialthatisnoncorrosiveinrelationtothesoilorporefluid.
low-friction material. Alternatively, a turntable or trimming
The inner surface shall be highly polished or shall be coated
lathe may be used.The cutting tool must be properly aligned to
with a low-friction material. Silicone grease or molybdenum
form a specimen of the same diameter as that of the ring.
disulfide is recommended; polytetrafluoroethylene is recom-
6.6 Deformation Indicator—To measure the axial deforma-
mended for nonsandy soils.
tion of the specimen with a resolution of 0.0025 mm [0.0001
6.3 Porous Disks—The porous disks shall be of silicon
in.] or better. Practice D6027/D6027M provides details on the
carbide, aluminum oxide, or other material of similar stiffness
evaluation of displacement transducers.
that is not corroded by the specimen or pore fluid. The disks
6.7 Recess Spacer Plate—A plate usually of acrylic with a
shall be fine enough that the soil will not penetrate into their
flat raised circular surface that fits inside the specimen ring and
pores, but have sufficient hydraulic conductivity so as not to
used to depress the top surface of the specimen about 2 mm
impede the flow of water from the specimen. Exact criteria
[0.08in]intothering.Asecondplatethatproducesabouttwice
have not been established but the disk thickness and hydraulic
the recess will be required when using a floating ring. The
conductivity should result in an impedance factor of at least
spacer plate(s) is not required if the consolidometer provides a
100.
means to center the porous disks.
NOTE 7—The impedance factor is defined as the ratio of the hydraulic
6.8 Balances—The balance(s) shall be suitable for deter-
conductivity of the stones times the drainage thickness of the soil to the
mining the mass of the specimen plus the containment ring and
hydraulic conductivity of the soil times the thickness of the stone. Bishop
and Gibson (1963) provides further information on the calculation and for making the water content measurements. The balance(s)
importance of the impedance factor.
shall be selected as discussed in Specification D4753. The
mass of specimens shall be determined to at least four
6.3.1 Diameter—The diameter of the top disk shall be 0.2 to
significant digits.
0.5 mm [0.01 to 0.02 in.] less than the inside diameter of the
ring. If a floating ring is used, the bottom disk shall meet the
6.9 Drying Oven—In accordance with Method D2216.
same requirement as the top disk.
6.10 Water Content Containers—In accordance with
NOTE 8—The use of tapered disks is recommended to prevent the disk Method D2216.
from binding with the inside of the ring.The surface matching l, the larger
6.11 Environment—Unless otherwise specified by the re-
diameter should be in contact with the soil or filter screen.
questing agency, the standard test temperature shall be in the
6.3.2 Thickness—Thickness of the disks shall be sufficient
range of 22 6 5 °C. In addition, the temperature of the
to prevent breaking. The top disk shall be loaded through a
consolidometer, test specimen, and submersion reservoir shall
corrosion-resistant plate of sufficient rigidity to prevent break-
not vary more than 6 2 °C throughout the duration of the test.
age of the disk.
Normally, this is accomplished by performing the test in a
6.3.3 Maintenance—The disks shall be clean and free from
room with a relatively constant temperature. If such a room is
cracks, chips, and nonuniformities. New porous disks should
not available, the apparatus shall be placed in an insulated
be boiled for at least 10 minutes and left in the water to cool to
chamber or other device that maintains the temperature within
ambient temperature before use. Immediately after each use,
the tolerance specified above. The apparatus should be located
clean the porous disks with a nonabrasive brush and boil or
in an area that does not have direct exposure to sunlight.
sonicate to remove clay particles that may reduce their perme-
6.12 Test Water—Water is necessary to saturate the porous
ability.
stones and fill the submersion reservoir. Ideally, this water
NOTE 9—It is recommended that porous disks be stored in clean test
would be similar in composition to the specimen pore fluid.
water between tests. Each drying cycle has the potential to draw particles
into the pores of the stone causing a progressive reduction in hydraulic Optionsincludeextractedporewaterfromthefield,potabletap
conductivity. When performing tests that require dry stones during the
water, demineralized water, or saline water. The requesting
setup procedure, the stones can be blotted dry just prior to the test.
agency should specify the water option. In the absence of a
6.4 Filter Screen—To prevent intrusion of material into the specification, the test should be performed with potable tap
pores of the porous disk, a filter screen may be placed between water.
D2435/D2435M − 11 (2020)
6.13 Miscellaneous Equipment—Including timing device 8.1.3 At each load applied, plot or tabulate the apparatus
with 1 s readability, spatulas, knives, and wire saws, used in deformations (corrections) to be applied to the measured
preparing the specimen.
deformation of the test specimen. The metal disk will also
deform; however, modification of the apparatus deformation
7. Sampling
due to this deformation will be negligible for all but extremely
7.1 Collection—Practices D1587/D1587M and D3550/
large stress levels. If necessary, the compression of the metal
D3550M cover procedures and apparatus that may be used to
disk can be computed and added to the corrections.
obtain intact samples generally satisfactory for testing. Speci-
8.1.4 When using nylon filter screens it may be possible to
mens may also be trimmed from large intact block samples
represent the corrections with a mathematical equation.
which have been fabricated and sealed in the field. Finally,
8.2 Miscellaneous Loading Elements—Determine the cu-
remolded specimens may be prepared from bulk samples to
mulative mass (to the nearest 0.001 kg) of the top porous disk
density and moisture conditions stipulated by the agency
plus any other apparatus components that rest on the specimen
requesting the test.
and are not counterbalanced by the load frame, M .
a
7.2 Transport—Intact samples intended for testing in accor-
dance with this test method shall be preserved, handled, and
8.3 Apparatus Constants—The following measurements
transportedinaccordancewiththepracticesforGroupCandD
must be made on an annual schedule or after replacement or
samples in Practices D4220/D4220M. Bulk samples for re-
alteration.
molded specimens should be handled and transported in
8.3.1 Determine the height of the ring, H , to the nearest
r
accordance with the practice for Group B samples.
0.01mm[0.0005in],thediameterofthering,D ,tothenearest
r
7.3 Storage—Storage of sealed samples should be such that 0.01 mm [0.0005 in], and the mass of the ring, M,tothe
r
nearest 0.01 gm.
nomoistureislostduringstorage,thatis,noevidenceofpartial
drying of the ends of the samples or shrinkage.Time of storage
8.3.2 Determine the thickness of the filter screen, H ,tothe
fs
should be minimized, particularly when the soil or soil mois-
nearest 0.01 mm [0.0005 in].
ture is expected to react with the sample tubes.
8.3.3 Determine the thickness of the step in the recess
7.4 Disturbance—The quality of consolidation test results spacer(s), H , to the nearest 0.01 mm [0.0005 in].
rs
diminishes greatly with sample disturbance. No sampling
procedure can ensure completely undisturbed samples. 9. Specimen Preparation
Therefore, careful examination of the sample is essential in
9.1 Reduce as much as practical any disturbance of the soil
selection of specimens for testing.
or changes in moisture and density during specimen prepara-
NOTE 11—Examination for sample disturbance, stones, or other
tion. Avoid vibration, distortion, and compression.
inclusions, and selection of specimen location is greatly facilitated by
x-ray radiography of the samples (see Methods D4452). 9.2 Prepare test specimens in an environment where soil
moisture change during preparation is minimized.
8. Calibration
NOTE 12—Ahigh humidity environment is often used for this purpose.
8.1 Apparatus Deformation—The measured axial deforma-
tionsshallbecorrectedforapparatuscompressibilitywhenever
9.3 Trim the specimen and insert it into the consolidation
the equipment deformation exceeds 0.1 % of the initial speci-
ring. The specimen must fit tightly in the ring without any
men height or when using paper filter screens. If the correction
perimeter gaps. When specimens come from intact soil col-
is warranted at any point during the test, then a correction
lected using sample tubes, the inside diameter of the tube shall
should be applied using the calibration data to all measure-
be at least 5 mm [0.25 in.] greater than the inside diameter of
ments throughout the test.
the consolidation ring, except as noted in 9.4 and 9.5.Itis
8.1.1 Assemble the consolidometer with a copper,
recommended that either a trimming turntable or cylindrical
aluminum, or hard steel disk of approximately the same height
cuttingringbeusedtocutthesoiltotheproperdiameter.When
as the test specimen and at least 1 mm [0.04 in.] smaller in
using a trimming turntable, make a complete perimeter cut,
diameter than the ring, but no more than 5 mm smaller in
reducing the specimen diameter to the inside diameter of the
diameter than the ring, in place of the specimen. Moisten the
consolidation ring. Carefully insert the specimen into the
porous disks. If paper filter screens are to be used (see 6.3),
consolidation ring, by the width of the cut, with a minimum of
they should be moistened and sufficient time (a minimum of 2
force. Repeat until the specimen protrudes from the bottom of
min.) allowed for the moisture to be squeezed from them
the ring. When using a cylindrical cutting ring, trim the soil to
during each increment of the calibration process.
a gentle taper in front of the cutting edge. After the taper is
8.1.2 Load and unload the consolidometer as in the test and
formed, advance the cutter a small distance to form the final
measure the deformation for each load applied. When using
diameter. Repeat the process until the specimen protrudes from
paper filter screens, it is imperative that calibration be per-
the ring.
formed following the exact loading and unloading schedule to
9.4 Fibroussoils,suchaspeat,andthosesoilsthatareeasily
be used in the test. This is due to the inelastic deformation
characteristics of filter paper. Recalibration should be done on damaged by trimming, may be transferred directly from the
an annual basis, or after replacement and reassembly of sampling tube to the ring, provided that the ring has the same
apparatus components. or slightly smaller inside diameter as the sample tube.
D2435/D2435M − 11 (2020)
9.5 Specimens obtained using a ring-lined sampler may be 9.10 If sufficient material is available, obtain at least two
used without prior trimming, provided they comply with the natural water content determinations of the soil in accordance
with Method D2216 from material trimmed adjacent to the test
requirements of Practice D3550/D3550M and the rigidity
specimen.
requirement of 6.2.4.
9.11 When index properties are specified by the requesting
9.6 Trim the specimen flush with the plane ends of the ring.
agency, store the remaining trimmings taken from around the
For soft to medium soils, a wire saw should be used for
specimen and determined to be similar material in a sealed
trimming the top and bottom of the specimen to minimize
container for determination as described in Section 10.
smearing.Astraightedgewithasharpcuttingedgemaybeused
for the final trim after the excess soil has first been removed
10. Soil Index Property Determinations
with a wire saw. For stiff soils, a sharpened straightedge alone
10.1 The determination of index properties is an important
should be used for trimming the top and bottom. If a small
adjuncttobutnotarequirementoftheconsolidationtest.These
particle is encountered in any surface being trimmed, it should
determinations when specified by the requesting agency shall
be removed and the resulting void filled with soil from the
be made on the most representative material possible. When
trimmings.
testing uniform materials, all index tests may be performed on
adjacent trimmings collected in 9.11. When samples are
NOTE 13—If large particles are found in the material during trimming
heterogeneous or trimmings are in short supply, index tests
or in the specimen after testing, include in the report this visual
observation or the results of a particle size analysis in accordance with should be performed on material from the test specimen as
Method D422 (except the minimum sample size requirement shall be
obtained in 11.6, plus representative trimmings collected in
waived).
9.11.
9.6.1 Unless the consolidometer provides a means to center
10.2 Specific Gravity—The specific gravity shall be deter-
the porous disks, the specimen must be recessed slightly below mined in accordance with Test Method D854 on material from
the top of the ring and also the bottom of the ring when using
the sample as specified in 10.1. The specific gravity from
a floating ring geometry. This is to facilitate centering of the another sample judged to be similar to that of the test specimen
top (and bottom) porous disk. After trimming the top surface may be used for calculation in 12.2.4 whenever an accurate
void ratio is not needed.
flush with the ring cover the specimen surface with the filter
screen and then use the recess spacer to partially extrude the
10.3 A
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