ASTM D4647/D4647M-13(2020)
(Test Method)Standard Test Methods for Identification and Classification of Dispersive Clay Soils by the Pinhole Test
Standard Test Methods for Identification and Classification of Dispersive Clay Soils by the Pinhole Test
SIGNIFICANCE AND USE
5.1 The pinhole test provides one method of identifying the dispersive characteristics of clay soils that are to be or have been used in earth construction. The piping failures of a number of homogeneous earth dams, erosion along channel or canal banks, and rainfall erosion of earthen structures have been attributed to the colloidal erosion along cracks or other flow channels formed in masses of dispersive clay (2).
5.2 This test method models the action of water flowing along a crack in an earth embankment. Other indirect tests, such as the double hydrometer test (Test Method D4221), the crumb test (3, 4), that relates the turbidity of a cloud of suspended clay colloids as an indicator of the clay dispersivity, and chemical tests that relate the percentage of sodium to total soluble salt content of the soil are also used as indicator tests of clay dispersibility (2). The comparison of results from the pinhole test and other indirect tests on hundreds of samples indicates that the results of the pinhole test have the best correlation with the erosional performance of clay soils in nature.
5.3 Method A and Method C of the pinhole test require the evaluation of cloudiness of effluent, final size of the pinhole, and computation of flow rates through the pinhole in order to classify the dispersive characteristics of the soil. Method B requires only the evaluation of the cloudiness of effluent and final size of the pinhole to classify the dispersive characteristics of the soil. The computation of flow rates through the pinhole in Method A serves primarily as a guide to the proper equipment and specimen performance under sequential pressures applied during the test. All methods produce similar results and any method can be used to identify dispersive clays.
5.4 The use of Method A or Method C results in the accumulation of data relative to sequential flow rates through the pinhole and consequent enlargement or erosion of the hole. The pinhole erosion test was dev...
SCOPE
1.1 This test method presents a direct, measurement of the dispersibility and consequent colloidal erodibility of clay soils by causing water to flow through a small hole punched in a specimen. The results of the tests are qualitative and provide general guidance regarding dispersibility and erodibility. This test method is complemented by Test Method D4221.
1.2 This test method and the criteria for evaluating test data are based upon results of several hundred tests on samples collected from embankments, channels, and other areas where clay soils have eroded or resisted erosion in nature (1).2
1.3 Three alternative procedures for classifying the dispersibility of clay soils are provided as follows:
1.3.1 Method A and Method C, adapted from Ref (1), classify soils into six categories of dispersiveness as: dispersibility (D1, D2), slight to moderately dispersive (ND4, ND3), and nondispersive (ND2, ND1).
1.3.2 Method B classifies soils into three categories of dispersiveness as: dispersibility (D), slightly dispersive (SD), and nondispersive (ND).
1.4 All observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice D6026.
1.5 Units—The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.
1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.7 This international standard was developed in accordance with internationally recognized principles...
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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: D4647/D4647M −13 (Reapproved 2020)
Standard Test Methods for
Identification and Classification of Dispersive Clay Soils by
the Pinhole Test
This standard is issued under the fixed designation D4647/D4647M; 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* priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use.
1.1 This test method presents a direct, measurement of the
1.7 This international standard was developed in accor-
dispersibility and consequent colloidal erodibility of clay soils
dance with internationally recognized principles on standard-
by causing water to flow through a small hole punched in a
ization established in the Decision on Principles for the
specimen. The results of the tests are qualitative and provide
Development of International Standards, Guides and Recom-
general guidance regarding dispersibility and erodibility. This
mendations issued by the World Trade Organization Technical
test method is complemented by Test Method D4221.
Barriers to Trade (TBT) Committee.
1.2 This test method and the criteria for evaluating test data
are based upon results of several hundred tests on samples
2. Referenced Documents
collected from embankments, channels, and other areas where
2.1 ASTM Standards:
clay soils have eroded or resisted erosion in nature (1).
D422 Test Method for Particle-SizeAnalysis of Soils (With-
1.3 Three alternative procedures for classifying the dispers-
drawn 2016)
ibility of clay soils are provided as follows:
D653 Terminology Relating to Soil, Rock, and Contained
1.3.1 Method A and Method C, adapted from Ref (1),
Fluids
classify soils into six categories of dispersiveness as: dispers-
D698 Test Methods for Laboratory Compaction Character-
ibility (D1, D2), slight to moderately dispersive (ND4, ND3),
istics of Soil Using Standard Effort (12,400 ft-lbf/ft (600
and nondispersive (ND2, ND1).
kN-m/m ))
1.3.2 Method B classifies soils into three categories of
D2216 Test Methods for Laboratory Determination of Water
dispersiveness as: dispersibility (D), slightly dispersive (SD),
(Moisture) Content of Soil and Rock by Mass
and nondispersive (ND).
D2487 Practice for Classification of Soils for Engineering
Purposes (Unified Soil Classification System)
1.4 All observed and calculated values shall conform to the
D2488 Practice for Description and Identification of Soils
guidelines for significant digits and rounding established in
(Visual-Manual Procedures)
Practice D6026.
D3740 Practice for Minimum Requirements for Agencies
1.5 Units—The values stated in either SI units or inch-
Engaged in Testing and/or Inspection of Soil and Rock as
pound units are to be regarded separately as standard. The
Used in Engineering Design and Construction
values stated in each system may not be exact equivalents;
D4221 Test Method for Dispersive Characteristics of Clay
therefore,eachsystemshallbeusedindependentlyoftheother.
Soil by Double Hydrometer
Combining values from the two systems may result in non-
D4318 Test Methods for Liquid Limit, Plastic Limit, and
conformance with the standard.
Plasticity Index of Soils
1.6 This standard does not purport to address all of the
D4753 Guide for Evaluating, Selecting, and Specifying Bal-
safety concerns, if any, associated with its use. It is the
ances and Standard Masses for Use in Soil, Rock, and
responsibility of the user of this standard to establish appro-
Construction Materials Testing
D6026 Practice for Using Significant Digits in Geotechnical
Data
ThistestmethodisunderthejurisdictionofASTMCommitteeD18onSoiland
RockandisthedirectresponsibilityofSubcommitteeD18.06onPhysical-Chemical
Interactions of Soil and Rock. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Feb. 1, 2020. Published February 2020. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1987. Last previous edition approved in 2013 as D4647 – 13. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/D4647_D4647M-13R20. the ASTM website.
2 4
The boldface numbers in parentheses refer to the list of references at the end of The last approved version of this historical standard is referenced on
these test methods. www.astm.org.
*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
D4647/D4647M − 13 (2020)
3. Terminology requires only the evaluation of the cloudiness of effluent and
finalsizeofthepinholetoclassifythedispersivecharacteristics
3.1 Definitions:
of the soil. The computation of flow rates through the pinhole
3.1.1 For definitions of terms in these test methods, refer to
in Method A serves primarily as a guide to the proper
Terminology D653.
equipment and specimen performance under sequential pres-
3.2 Definitions of Terms Specific to This Standard:
sures applied during the test. All methods produce similar
3.2.1 dispersive clays—clays that disaggregate easily and
resultsandanymethodcanbeusedtoidentifydispersiveclays.
rapidly in water of low-salt concentration, and without signifi-
cant mechanical assistance. Such clays usually have a high 5.4 The use of Method A or Method C results in the
proportion of their adsorptive capacity saturated with sodium
accumulation of data relative to sequential flow rates through
cations. the pinhole and consequent enlargement or erosion of the hole.
3.2.1.1 Discussion—Such clays generally have a high
The pinhole erosion test was developed for the purpose of
shrink-swellpotential,havelowresistancetoerosion,andhave identifying dispersive soils and is not intended to be a
low permeability in an intact state.
geometrically scaled model of a prototype structure. Since the
theory of similitude was not used in the design of the pinhole
4. Summary of Test Method
test, quantitative data are not obtained. The quantity of flow
through the pinhole, amount of soil erosion, or the rate of soil
4.1 The test method is started with distilled water flowing
erosion should not be extrapolated to actual field conditions
horizontally under a hydraulic head of 50 mm [2 in.] through
(3). However, such data may be useful in performing qualita-
a 1.0-mm [0.04-in.] diameter hole punched in the soil speci-
tive evaluations of the consequences of such erosion in terms
men. The nature of the solution emerging from the specimen
of dam failure, loss of life and property.They also may be used
under the initial 50-mm [2-in.] head provides the principle
in considering the cost effectiveness of defensive design
differentiation between dispersive and nondispersive clays.
measures necessary to minimize the effects of failure due to
Flow from dispersive clays will be distinctly dark and the hole
dispersive clays. For example, the amount of colloidal erosion
through the specimen will enlarge rapidly, with a resultant
that will occur in a soil classed as ND2 (very slightly
increase in the flow rate. Flow from slightly to moderately
dispersive) will be very small for a relatively long period of
dispersive clays will be slightly dark with a constant hole size
time. Such erosion may not be significant in evaluating the
and flow rate. Flow from nondispersive clays will be com-
cost-benefit relationships in projects where public safety is not
pletely clear with no measurable increase in the hole size.
involved or where normal maintenance procedures will handle
4.2 Test results are evaluated from the appearance of the
the problem. In such cases, classifying the soil as ND (nondis-
flowing solution emerging from the specimen, the rate of flow,
persive) using Method B of the pinhole test should be
and the final size of the hole through the specimen. These
adequate.
observations provide the basis for classifying the soil speci-
5.5 Pinhole tests that result in classifying soil as slightly
men.
dispersive (ND3 by Method A or Method C or SD by Method
5. Significance and Use B) indicate high uncertainty about the existence of significant
problems to be considered in the design or stability of a
5.1 The pinhole test provides one method of identifying the
structure. In such cases, it is advisable to resample and test a
dispersive characteristics of clay soils that are to be or have
number of other soils from the same area to generate an
been used in earth construction. The piping failures of a
adequate statistical sample for problem evaluation. The origi-
number of homogeneous earth dams, erosion along channel or
nal slightly dispersive sample may come from an area on the
canal banks, and rainfall erosion of earthen structures have
edge of a more highly dispersive soil.
been attributed to the colloidal erosion along cracks or other
flow channels formed in masses of dispersive clay (2).
5.6 In a few physiographic areas or geoclimatic conditions,
or both, neither the pinhole test nor the other indicator tests
5.2 This test method models the action of water flowing
provide consistent identification of dispersive clays (5, 6, 7).In
along a crack in an earth embankment. Other indirect tests,
such cases, the results of the tests (8, 9) should be evaluated in
such as the double hydrometer test (Test Method D4221), the
terms of cost effectiveness and design judgment (7).
crumb test (3, 4), that relates the turbidity of a cloud of
suspended clay colloids as an indicator of the clay dispersivity,
5.7 For some projects, it may be desirable to perform the
and chemical tests that relate the percentage of sodium to total
pinhole test using eroding fluids other than distilled water (8,
soluble salt content of the soil are also used as indicator tests
10). In such cases, MethodA, Method B, or Method C may be
of clay dispersibility (2). The comparison of results from the
used to identify the dispersive characteristics of the soil and
pinhole test and other indirect tests on hundreds of samples
compare the results with those obtained using distilled water.
indicates that the results of the pinhole test have the best
NOTE 1—Notwithstanding the statement on precision and bias con-
correlation with the erosional performance of clay soils in
tained in these test methods: The precision of these test methods is
nature.
dependent on the competence of the personnel performing it, and the
suitability of the equipment and facilities used. Agencies which meet the
5.3 Method A and Method C of the pinhole test require the
criteria of Practice D3740 are generally considered capable of competent
evaluation of cloudiness of effluent, final size of the pinhole,
and objective testing. Users of these test methods are cautioned that
and computation of flow rates through the pinhole in order to
compliance with Practice D3740 does not in itself assure reliable testing.
classify the dispersive characteristics of the soil. Method B Reliable testing depends on several factors; Practice D3740 provides a
D4647/D4647M − 13 (2020)
means of evaluating some of those factors.
7.1.1 Method A: D1, D2—Dispersive clays that fail rapidly
under 50-mm [2-in.] head.
6. Limitations
ND4, ND3—Slightly to moderately dispersive clays that
6.1 Development of the test procedure to provide reproduc-
erode slowly under 50-mm [2-in.] or 180-mm [7-in.] head.
ible results that differentiate between clay soils that were
ND2, ND1—Nondispersive clay with very slight to no
known to be erodible (dispersive) and nonerodible (nondisper-
colloidal erosion under 380-mm [15-in.] or 1020-mm [40-in.]
sive) in the field indicates the following limitations in the use
head.
of this test:
7.1.2 Method B: D—Dispersive clays that erode rapidly
6.1.1 This test method is not applicable to soils with less
under 50-mm [2-in.] head.
than 12 % finer than 0.005 mm and with a plasticity index less
SD—Slightly dispersive clays that erode slowly under
than or equal to 4 (2, 11). Such soils generally have low
180-mm [7-in.] head.
resistance to erosion regardless of dispersive characteristics.
ND—Nondispersive clays that show very slight or no
6.1.2 The most consistent results are produced when the
colloidal erosion under 380-mm [15-in.] head.
natural water content of the sample is preserved during the
NOTE 2—Method B for classifying dispersiveness of clay soils com-
sampling, shipping, storage, and testing operations.
bines the categories of Method A as follows: D = D1, D2, ND4;
6.1.3 A few instances have been reported in which the
SD = ND3; and ND = ND2, ND1.
pinhole test did not identify some dispersive clays in which the
7.1.3 Method C: D1, D2—Dispersive clays that fail rapidly
porewatercontainedlessthan0.4meq/Ltotalsolublesaltsthat
under 50-mm [2-in.] head.
were more than 80 % sodium salts.
ND4, ND3—Dispersive clays that erode slowly under
6.1.4 This test method was developed to test specimens of
50-mm [2-in.], 180-mm [7-in.], or 380-mm [15-in.] head.
disturbedsoilthatarecompactedintothetestcylinder.Thistest
ND2, ND1—Nondispersive clay with very slight to no
method can also be used to test intact specimens when they are
colloidal erosion under 380-mm [15-in.] head.
properly trimmed and sealed into the test cylinder; however,
some investigators (6) have found that these test methods are
8. Apparatus
not applicable in evaluating the dispersive characteristics of
intact specimens of highly sensitive clays. Such clays may be
8.1 Pinhole Test Apparatus—Typical pinhole test apparatus
classed as dispersive from the pinhole test results but perform is shown in Fig. 1, Fig. 2, and Fig. 3. Various other types and
as nondispersive materials in nature.
sizes of specimen molds or containers and top and base plates
6.1.5 This test method is performed with distilled water, at may be used provided the test specimen is 38 mm [1.5 in.]
a pH of 5.5 to 7.0, as the eroding fluid. The use of water with
long, the pinhole is 1.0 mm [0.04 in.] in diameter, and the hole
various ionic concentrations and combinations will alter the
through the truncated cone centering guide or other centering
results of the test (8, 10).
device is 1.5 mm [0.059 in.] in diameter.
8.1.1 It is important that the outlet drain be large enough to
7. Classification
accommodate the maximum inflow without creating a partial
7.1 The observations of these test
...
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