ASTM D2434-22

Standard Test Methods for Measurement of Hydraulic Conductivity of Coarse-Grained Soils

ABSTRACT
This test method covers the determination of the coefficient of permeability by a constant-head method for the laminar flow of water through granular soils. The procedure is to establish representative values of the coefficient of permeability of granular soils that may occur in natural deposits as placed in embankments, or when used as base courses under pavements. The different apparatus used in determining the granular soil permeability are presented. The methods in preparing the test specimen are presented in details. The testing and calculation procedure for granular soil permeability determination are presented.
SIGNIFICANCE AND USE
5.1 These test methods are used to measure one-dimensional vertical flow of water through initially saturated coarse-grained, pervious (that is, free-draining) soils under an applied hydraulic gradient. Hydraulic conductivity of coarse-grained soils is used in various civil engineering applications. These test methods are suitable for determination of hydraulic conductivity for soils with k > 10–7 m/s.
Note 2: Clean coarse-grained soils that are classified using Practice D2487-17 as GP, GW, SP, and SW can be tested using these test methods. Depending on fraction and characteristics of fine-grained particles present in soils, these test methods may be suitable for testing other soil types with fines content greater than 5 % (for example, GP-GC, SP-SM).  
5.2 Coarse-grained soils are to be tested at a void ratio representative of field conditions. For engineered fills, compaction specification can be used to provide target test conditions, whereas for natural soils, field testing of in-situ density can be used to provide target test conditions.  
5.3 Use of a dual-ring permeameter is included in these test methods in addition to a single-ring permeameter for the rigid wall test apparatus. The dual-ring permeameter allows for reducing potential adverse effects of sidewall leakage on measured hydraulic conductivity of the test specimens. The use of a plate at the outflow end of the specimen that contains a ring with a diameter smaller than the diameter of the permeameter and the presence of two outflow ports (one from the inner ring, one from the annular space between the inner ring and the permeameter wall) allows for separating the flow from the central region of the test specimen from the flow near the sidewall of the permeameter.
Note 3: Sidewall leakage has been reported to have significant influence on flow conditions for coarse-grained soils due to presence of larger voids at the boundary and higher void ratio in this region of the specimen. Three modificat...
SCOPE
1.1 These test methods cover laboratory measurement of the hydraulic conductivity (also referred to as coefficient of permeability) of water-saturated coarse-grained soils (for example, sands and gravels) with k > 10–7 m/s. The test methods utilize low hydraulic gradient conditions.  
1.2 This standard describes two methods (A and B) for determining hydraulic conductivity of coarse-grained soils. Method A incorporates use of a rigid wall permeameter and Method B incorporates the use of a flexible wall permeameter. A single- or dual-ring rigid wall permeameter may be used in Method A. A dual-ring permeameter may be preferred over a single-ring permeameter when adverse effects from short-circuiting of permeant water along the sidewalls of the permeameter (that is, prevent sidewall leakage) are suspected by the user of this standard.  
1.3 The test methods are used under constant head conditions.  
1.4 The test methods are used under saturated soil conditions.  
1.5 Water is used to permeate the test specimen with these test methods.  
1.6 Units—The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
Note 1: Hydraulic conductivity has traditionally been reported in cm/s in the US, even though the official SI unit for hydraul...

General Information

• Status: Published
• Publication Date: 14-Mar-2022
• ICS: 93.020 - Earthworks. Excavations. Foundation construction. Underground works
• Technical Committee: D18 - Soil and Rock
• Drafting Committee: D18.04 - Hydrologic Properties and Hydraulic Barriers

Relations

• Refers: ASTM D4753-24 - Standard Guide for Evaluating, Selecting, and Specifying Balances and Standard Masses for Use in Soil, Rock, and Construction Materials Testing
• Effective Date: 01-Feb-2024
• Refers: ASTM D5101-23 - Standard Test Method for Measuring the Filtration Compatibility of Soil-Geotextile Systems
• Effective Date: 01-Nov-2023
• Refers: ASTM D3740-23 - Standard Practice for Minimum Requirements for Agencies Engaged in Testing and/or Inspection of Soil and Rock as Used in Engineering Design and Construction
• Effective Date: 01-Nov-2023
• Refers: ASTM D3740-19 - Standard Practice for Minimum Requirements for Agencies Engaged in Testing and/or Inspection of Soil and Rock as Used in Engineering Design and Construction
• Effective Date: 01-Oct-2019
• Refers: ASTM D2487-17e1 - Standard Practice for Classification of Soils for Engineering Purposes (Unified Soil Classification System)
• Effective Date: 15-Dec-2017
• Refers: ASTM D2487-17 - Standard Practice for Classification of Soils for Engineering Purposes (Unified Soil Classification System)
• Effective Date: 15-Dec-2017
• Refers: ASTM D5101-12(2017) - Standard Test Method for Measuring the Filtration Compatibility of Soil-Geotextile Systems
• Effective Date: 15-Feb-2017
• Refers: ASTM D5716/D5716M-15 - Standard Test Method for Measuring the Rate of Well Discharge by Circular Orifice Weir
• Effective Date: 01-Nov-2015
• Refers: ASTM D4753-15 - Standard Guide for Evaluating, Selecting, and Specifying Balances and Standard Masses for Use in Soil, Rock, and Construction Materials Testing
• Effective Date: 01-May-2015
• Refers: ASTM D653-14 - Standard Terminology Relating to Soil, Rock, and Contained Fluids
• Effective Date: 01-Aug-2014
• Refers: ASTM D5101-12 - Standard Test Method for Measuring the Filtration Compatibility of Soil-Geotextile Systems
• Effective Date: 01-Jul-2012
• Refers: ASTM D3740-12a - Standard Practice for Minimum Requirements for Agencies Engaged in Testing and/or Inspection of Soil and Rock as Used in Engineering Design and Construction
• Effective Date: 01-May-2012
• Refers: ASTM D3740-12 - Standard Practice for Minimum Requirements for Agencies Engaged in Testing and/or Inspection of Soil and Rock as Used in Engineering Design and Construction
• Effective Date: 01-Mar-2012
• Refers: ASTM D653-11 - Standard Terminology Relating to Soil, Rock, and Contained Fluids
• Effective Date: 01-Sep-2011
• Refers: ASTM D3740-11 - Standard Practice for Minimum Requirements for Agencies Engaged in Testing and/or Inspection of Soil and Rock as Used in Engineering Design and Construction
• Effective Date: 01-Sep-2011

Overview

ASTM D2434-22: Standard Test Methods for Measurement of Hydraulic Conductivity of Coarse-Grained Soils is an internationally recognized standard developed by ASTM International for determining the hydraulic conductivity, or coefficient of permeability, of water-saturated coarse-grained soils (such as sands and gravels) using constant-head test methods. These laboratory procedures are vital for evaluating the behavior of free-draining, pervious soils under laminar flow conditions and provide foundational data for a wide range of geotechnical and civil engineering applications.

The test methods outlined in ASTM D2434-22 focus on soils with hydraulic conductivity values greater than 10⁻⁷ m/s, under saturated and constant hydraulic gradient conditions. The standard describes the use of both rigid wall and flexible wall permeameters, and addresses critical concerns such as sidewall leakage and specimen preparation to ensure accurate, reproducible results.

Key Topics

• Hydraulic Conductivity Measurement
  Methods for laboratory measurement of the hydraulic conductivity (coefficient of permeability) of coarse-grained soils using constant-head permeameters.

• Apparatus and Equipment

  • Rigid wall permeameters (including single and dual-ring variants)
  • Flexible wall permeameters
  • Constant-head hydraulic systems
  • Flow-measurement devices
  • Pressure application systems
    The selection and configuration of apparatus are based on soil characteristics and test objectives.

• Test Specimen Preparation
  Detailed procedures for preparing, compacting, and saturating soil specimens at conditions representative of field placement or natural deposits.

• Mitigating Sidewall Leakage
  Use of a dual-ring permeameter and other mitigation strategies to reduce measurement errors caused by water “short-circuiting” along the specimen boundary.

• Calculation and Data Validity
  Instructions for applying Darcy's law, ensuring laminar flow and steady hydraulic gradient, and confirming the linearity between hydraulic gradient and flow velocity.

• Types of Soils Tested
  The method is most suitable for soils classified as GP, GW, SP, and SW (per ASTM D2487), but can sometimes be extended to soils with minor fines contents.

Applications

• Geotechnical Engineering Design
  Accurate measurement of hydraulic conductivity is critical in designing foundations, embankments, and engineered fills. The data helps predict drainage characteristics, settlement, pore pressure changes, and the potential for piping or erosion.

• Infrastructure Construction
  Used in evaluating materials for road and pavement base courses, ensuring suitable drainage, and mitigating frost heave or saturation-related failures.

• Hydrogeology & Environmental Assessment
  Key for modeling groundwater flow, evaluating aquifer properties, and designing retention ponds, filters, or drainage layers in landfills and containment systems.

• Quality Control in Construction
  Verifies that compacted soils or aggregates meet specified permeability requirements for performance and durability in the field.

• Research and Development
  Supports academic and industrial studies involving soil-water interaction, porous media flow, and improvements to construction materials.

Related Standards

The following ASTM standards are referenced or related to hydraulic conductivity testing of soils:

• ASTM D653: Terminology Relating to Soil, Rock, and Contained Fluids
• ASTM D2487: Classification of Soils for Engineering Purposes (Unified Soil Classification System)
• ASTM D3740: Minimum Requirements for Agencies Engaged in Testing and/or Inspection of Soil and Rock
• ASTM D4753: Guide for Evaluating, Selecting, and Specifying Balances and Standard Masses
• ASTM D6913/D6913M: Particle-Size Distribution (Gradation) of Soils Using Sieve Analysis
• ASTM D6026: Practice for Using Significant Digits and Data Records in Geotechnical Data

Compliance with ASTM D2434-22 ensures standardized, reproducible permeability test results, directly supporting reliable geotechnical assessments and infrastructure design worldwide. Including ASTM D2434-22 in project specifications ensures best practices in the measurement of soil hydraulic properties, supporting both regulatory and technical requirements in the geotechnical sector.

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: D2434 − 22
Standard Test Methods for
Measurement of Hydraulic Conductivity of Coarse-Grained
Soils
This standard is issued under the fixed designation D2434; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope* responsibility of the user of this standard to establish appro-
priate safety, health, and environmental practices and deter-
1.1 Thesetestmethodscoverlaboratorymeasurementofthe
mine the applicability of regulatory limitations prior to use.
hydraulic conductivity (also referred to as coeffıcient of per-
1.9 This international standard was developed in accor-
meability) of water-saturated coarse-grained soils (for
–7 dance with internationally recognized principles on standard-
example, sands and gravels) with k >10 m/s. The test
ization established in the Decision on Principles for the
methods utilize low hydraulic gradient conditions.
Development of International Standards, Guides and Recom-
1.2 This standard describes two methods (A and B) for
mendations issued by the World Trade Organization Technical
determining hydraulic conductivity of coarse-grained soils.
Barriers to Trade (TBT) Committee.
Method A incorporates use of a rigid wall permeameter and
Method B incorporates the use of a flexible wall permeameter. 2. Referenced Documents
A single- or dual-ring rigid wall permeameter may be used in
2.1 ASTM Standards:
Method A. A dual-ring permeameter may be preferred over a
D653Terminology Relating to Soil, Rock, and Contained
single-ring permeameter when adverse effects from short-
Fluids
circuiting of permeant water along the sidewalls of the per-
D2487Practice for Classification of Soils for Engineering
meameter (that is, prevent sidewall leakage) are suspected by
Purposes (Unified Soil Classification System)
the user of this standard.
D3740Practice for Minimum Requirements for Agencies
Engaged in Testing and/or Inspection of Soil and Rock as
1.3 The test methods are used under constant head condi-
tions. Used in Engineering Design and Construction
D4753Guide for Evaluating, Selecting, and Specifying Bal-
1.4 The test methods are used under saturated soil condi-
ances and Standard Masses for Use in Soil, Rock, and
tions.
Construction Materials Testing
1.5 Water is used to permeate the test specimen with these
D5101Test Method for Measuring the Filtration Compat-
test methods.
ibility of Soil-Geotextile Systems
D5716/D5716MTest Method for Measuring the Rate of
1.6 Units—The values stated in SI units are to be regarded
Well Discharge by Circular Orifice Weir
asstandard.Nootherunitsofmeasurementareincludedinthis
D6026Practice for Using Significant Digits and Data Re-
standard.
cords in Geotechnical Data
NOTE1—Hydraulicconductivityhastraditionallybeenreportedincm/s
D6913/D6913MTest Methods for Particle-Size Distribution
in the US, even though the official SI unit for hydraulic conductivity is
(Gradation) of Soils Using Sieve Analysis
m/s.
1.7 Theobservedandcalculatedvaluesshallconformtothe
3. Terminology
guidelines for significant digits and rounding established in
3.1 Definitions:
Practice D6026.
3.1.1 For definitions of common technical terms in this
1.8 This standard does not purport to address all of the
standard, refer to Terminology D653.
safety concerns, if any, associated with its use. It is the
3.1.2 hydraulic conductivity, k, n—(also referred to as coef-
ficient of permeability or permeability) the rate of discharge of
ThistestmethodisunderthejurisdictionofASTMCommitteeD18onSoiland
Rock and is the direct responsibility of Subcommittee D18.04 on Hydrologic
Properties and Hydraulic Barriers. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved March 15, 2022. Published March 2022. Originally contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
approved in 1965. Last previous edition approved in 2019 as D2434–19. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/D2434-22. 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
D2434 − 22
spreadingalayerofbentoniteandpetroleumjellymixturealongtheentire
water under laminar flow conditions through a unit cross-
surface area of the sidewall, and iii) using a closed-cell neoprene liner
sectional area of porous medium under a unit hydraulic
attached to the inside wall of the permeameter.
gradient and standard temperature conditions (20°C).
5.4 Use of a flexible wall permeameter is included in these
3.1.3 hydraulic gradient, i, n—the change in total head
test methods in addition to the rigid wall permeameters. The
(head loss, ∆h) per unit distance (L) in the direction of fluid
flexible wall permeameter reduces potential adverse effects of
flow, in whichi=∆h⁄L.
sidewallleakageonmeasuredhydraulicconductivityofthetest
3.1.4 permeameter, n—the apparatus (cell) containing the
specimens and allows for application of hydrostatic confining
test specimen in a hydraulic conductivity test.
stressconditionsonthespecimenduringthehydraulicconduc-
3.1.5 nominal particle size, n—the particle size correspond-
tivity test. Confining stress allows for representing field con-
ing to 75% passing [that is, D ] per methods inTest Methods ditions(thatis,simulatingstressstatesinthesubgradethatmay
D6913/D6913M.
affect values of k).
5.5 Darcy’s law is assumed to apply to the test conditions,
4. Summary of Test Method
flow is assumed to be laminar (see Note 4), and the hydraulic
4.1 The standard includes methods for determining the
conductivity is assumed to be considered independent of
hydraulic conductivity of free-draining soils (for example, hydraulic gradient. The validity of these assumptions may be
sands and gravels with low fines content) by permeating
evaluated by measuring the hydraulic conductivity of a speci-
samples with water under constant head conditions. Multiple men at three different hydraulic gradients. The discharge
methods are presented that include different permeameters
velocity (v = k× i) is plotted against the applied hydraulic
(rigid wall, dual-ring rigid wall, and flexible wall). Different gradient.Iftheresultingrelationshipislinearandthemeasured
options for constant head systems include reservoirs, Mariotte
hydraulicconductivityvaluesaresimilar(thatis,within25%),
Bottle, and a flow pump. then these assumptions are considered valid.
NOTE 4—Previous studies suggest that the limit between turbulent flow
5. Significance and Use
and laminar flow for soils occurs for Reynolds numbers between 1 and 10
(1 and 2) .Aformulation for Reynolds number (and division for laminar
5.1 These test methods are used to measure one-
and turbulent flow conditions) for flow through packed beds has been
dimensional vertical flow of water through initially saturated
reported (3).The formulation is presented for uniformly graded, spherical
coarse-grained, pervious (that is, free-draining) soils under an
particles in Eq 1.
applied hydraulic gradient. Hydraulic conductivity of coarse-
Dνρ
f
grained soils is used in various civil engineering applications. *
Re 5 (1)
µ 1 2 n
~ !
These test methods are suitable for determination of hydraulic
–7
conductivity for soils with k>10 m/s.
where:
Re* = Reynolds Number for packed bed flow,
NOTE 2—Clean coarse-grained soils that are classified using Practice
D = granule or particle diameter (m),
D2487-17 as GP, GW, SP, and SWcan be tested using these test methods.
v = superficial fluid velocity (that is, Darcy velocity) through bed
Depending on fraction and characteristics of fine-grained particles present
(m/s),
insoils,thesetestmethodsmaybesuitablefortestingothersoiltypeswith
ρ = fluid density (kg/m ),
f
fines content greater than 5% (for example, GP-GC, SP-SM).
µ = liquid viscosity (dynamic viscosity) (Pa s), and
5.2 Coarse-grained soils are to be tested at a void ratio
n = porosity of bed (expressed as a ratio).
representative of field conditions. For engineered fills, com-
Provisions are provided in (3) for establishing equivalent particle
diameterforuseinthisequationfornonuniformparticlesizedistributions
paction specification can be used to provide target test
and nonspherical particles.
conditions, whereas for natural soils, field testing of in-situ
NOTE 5—Using sufficiently low gradients has been demonstrated to be
density can be used to provide target test conditions.
important for obtaining representative results. Hydraulic gradients less
than0.05havebeenreported (4).Usingalongtestspecimen(ontheorder
5.3 Use of a dual-ring permeameter is included in these test
of 1.5 m) has been reported as an effective method for achieving
methods in addition to a single-ring permeameter for the rigid
appropriately low hydraulic gradients for materials with k > 0.01m⁄s.
wall test apparatus. The dual-ring permeameter allows for
NOTE 6—The quality of the result produced by this standard is
reducing potential adverse effects of sidewall leakage on
dependent of the competence of the personnel performing it and the
measuredhydraulicconductivityofthetestspecimens.Theuse suitability of the equipment and facilities used. Agencies that meet the
criteria of Practice D3740 are generally considered capable of competent
of a plate at the outflow end of the specimen that contains a
and objective testing, sampling, inspection, etc. Users of this standard are
ring with a diameter smaller than the diameter of the per-
cautioned that compliance with Practice D3740 does not in itself result in
meameter and the presence of two outflow ports (one from the
reliable values. Reliable results depend on many factors; Practice D3740
inner ring, one from the annular space between the inner ring
provides a means of evaluating some of those factors.
and the permeameter wall) allows for separating the flow from
6. Apparatus
the central region of the test specimen from the flow near the
sidewall of the permeameter.
6.1 Constant-Head Hydraulic System—The hydraulic sys-
NOTE 3—Sidewall leakage has been reported to have significant
temisusedtoapply,maintain,andmeasureheadsandresulting
influence on flow conditions for coarse-grained soils due to presence of
larger voids at the boundary and higher void ratio in this region of the
specimen.Three modifications that have been used to reduce this effect in
rigid wall permeameters include: i) placing a piping barrier (for example, The boldface numbers in parentheses refer to a list of references at the end of
caulk rings along every approximately 25-mm length of sidewall), ii) this standard.
D2434 − 22
hydraulic gradients in a test. The hydraulic system mainly measurement system may consist of a graduated accumulator,
consists of reservoirs that hold water and associated piping, Mariotte bottle, electromagnetic flow meter, flow pump (if
tubing, valves, and connections. See Note 7. Pressure applica- used to apply constant head), or other mass/volume-measuring
tion setups also may be used to pressurize influent and effluent device that has the resolution and accuracy required to deter-
liquids. The system shall be capable of maintaining constant mine flow to the tolerances provided above. In most cases,
hydraulic head to within 65% or better and shall include these devices are common to the hydraulic system.
means to measure the hydraulic pressures to within the 6.2.1 De-airing and Dimensional Stability of the System—
prescribed tolerances. In addition, the head loss must be held The flow-measurement system shall contain minimal dead
constant to 65% or better and shall be measured with space (volumetric space in the system that does not contribute
instruments providing the same accuracy and readability or to hydraulic fluid flow) and shall be equipped to allow for
better. Large-scale specimens have high flow capacities that complete and rapid de-airing so that the system remains
may require specialized systems such as large reservoirs to de-airedforthedurationoftesting.Dimensionalstabilityofthe
provide adequate flow rates (see 8.1). Two alternate means of system with respect to changes in pressure shall be accom-
achievingconstantheadconditionsforktestingincludedinthis plished by using a stiff flow-measurement system that includes
standard are: a) Mariotte Bottle and b) use of a flow pump. glass pipe or rigid metallic or thermoplastic tubing.
6.3 Pressure Application System—The system (if used) for
NOTE 7—Use of reservoirs with an overflow function (such as an outlet
pipe or overflow along the perimeter of a level reservoir) that remains at applying pressure on the coarse-grained soil specimen in the
a set elevation for the duration of testing have been demonstrated to work
permeameter shall allow for applying and controlling the
well and will reduce the potential for changes in head during a test.
pressure to within 65% of the set value. For a rigid wall
6.1.1 The head shall be measured with a rigid measuring permeameter (Method A), a vertical pressure application sys-
tem is used. The vertical pressure application system may
tape, graduated reservoir, engineer’s scale, pressure gage,
electronic pressure transducer, or other device that has the include a dead-weight load application setup; a hydraulic load
application system; or other system that allows for application
resolution and accuracy required for the determination of head
to the tolerances provided above. Hydraulic heads shall be of the desired level of pressure to a specimen via the top of the
specimen. The vertical effective stress on the test specimen
measured at points along the length of a test specimen using
piezometers and from the inflow and outflow elevations in the (which is the difference between the applied vertical pressure
case of a rigid-wall permeameter. Hydraulic heads shall be andtheporewaterpressure—providedasystemtocontrolpore
measuredfromtheinflowandoutflowelevationsinthecaseof waterpressureisused)shallbemaintainedtothedesiredvalue
a flexible-wall permeameter. If measurements at inflow and within 610% of set value. For a flexible wall permeameter
outflow measurement locations are to be used, the procedure (Method B), a system for pressurizing the permeameter cell
specified in 8.1 shall be conducted to verify that negligible shallbecapableofapplyingandcontrollingthecellpressureto
head loss occurs through the tubing and system residing within 65 % of the set value. The effective stress on the test
betweenthespecimenandtheinflowandoutflowmeasurement specimen(whichisthedifferencebetweenthecellpressureand
locations. A general configuration for piezometers is provided the pore water pressure) shall be maintained to the desired
inTest Method D5716/D5716M.Aporous filter is required for value within 610 % of set value. The device for pressurizing
piezometers used in hydraulic conductivity tests to avoid soils the cell may consist of a reservoir connected to the permeame-
cloggingthepiping.Ascreenplacedontheinsideofthenipple ter cell and partially filled with de-aired water, with the upper
part of the reservoir connected to a compressed gas supply or
assembly has been reported for such a filter (U.S.Army Corps
of Engineers (1980) Engineering and Design Laboratory Soils othersourceofpressure.Aminimumof2to3mofwater-filled
distance within the apparatus between the pressurized gas and
Testing, Engineer Manual no. 1110-2-1906).
thespecimenisrequired(seeNote8).Thegaspressureshallbe
6.1.2 System De-airing—The hydraulic system shall be
controlled by a pressure regulator and measured by a pressure
designed to facilitate rapid and complete removal of free air
gage,electronicpressuretransducer,orotherdevicecapableof
bubbles from flow lines. This removal can be accomplished,
measuring to the prescribed tolerances. A hydraulic system
for example, by using tubing and ball valves that are large
pressurizedbydeadweightactingonapistonorotherpressure
enough to prevent entrapment of air bubbles, are large enough
device capable of applying and controlling the permeameter
not to cause head losses as described in 8.1, and using fittings
cell pressure within the tolerances prescribed in this section
without pipe threads. Placement of valve(s) at points of high
may be used.
elevation within the hydraulic system can facilitate venting of
air from the system. If de-aired water is used as permeant
NOTE 8—De-aired water is commonly used for the cell fluid to reduce
water,useasystemwithsufficientcapacitytoproducede-aired
the potential for diffusive air transport through the membrane into the
specimen. Other fluids that have low gas solubilities such as oils, are also
water for the test duration. Recirculated permeant water shall
acceptable,providedtheydonotreactwithcomponentsofthepermeame-
not be used in the test.
ter. Also, use of a sufficiently long tube connecting the pressurized cell
liquid to the cell helps to delay the appearance of air in the cell fluid and
6.2 Flow-Measurement System—The flow-measurement
to reduce the flow of dissolved air into the cell.
system is used to determine the amount of flow through a
specimen during a test. The measurement device shall allow 6.4 Permeameter—The permeameter shall consist of a cell
forthemeasurementofthequantityofflow(inflow,outflow,or for containing the test specimen and attached equipment that
both inflow and outflow, if selected for verification of flow allow for connecting the cell to the hydraulic system, the
conditions) over an interval of time to within 65%. Flow- flow-measurementsystem,andthepressureapplicationsystem
D2434 − 22
(if applicable), as well as provisions to support a specimen and ingleakageortheplatemaybeperforatedandnotsealedtothe
to permeate the specimen. The permeameter shall consist of a permeametercellbasedonthedesignofthetestsetup.Asealed
cylindrical cell (rigid for Method A, flexible for Method B),
top plate is used when the hydraulic or flow measurement
coverplate,baseplate,andattachmentstoholdthecomponents
system, or both, are connected to the top plate (or the
together without leakage during a test. The diameter of the
permeameter cell) through leak-proof ports or valves, whereas
permeameter shall be determined based on the D (that is, the
95 a perforated top plate is used when water is ponded directly
particle size corresponding to 95% passing per methods in
above a specimen. The perforated plate shall not impede flow.
D6913/D6913M) of the soil to be tested. A permeameter
Theprocedurespecifiedin8.1shallbeconductedtoverifythat
diameter at least 10 times D is required. The permeameter
this criterion is satisfied. The top plate shall be designed to
length shall be greater than 6 times D .
distribute permeant water to the cross section of the specimen
6.5 Rigid Wall Permeameter (MethodA)—Thepermeameter such that flow through the test specimen is one-dimensional.
shallconsistofarigid-wallcellintowhichthesoilspecimento
6.5.2 Base Plate—The bottom plate shall be constructed of
betestedisplacedandinwhichthetestspecimenispermeated.
a rigid material that does not react adversely with the test
The permeameter shall be constructed of a rigid material such
material or permeant water. The base plate shall be sealed to
as steel, aluminum, brass, or plastic that will not be damaged
the rigid-wall permeameter cell using an O-ring or similar
during placement/compression/compaction of the specimen in
preventing leakage. The plate shall be designed to distribute
the cell. The cross-sectional area along the direction of flow
permeant water to the cross section of the specimen such that
shallnotvarybymorethan 62%andtheheightshallnotvary
flow through the test specimen is one-dimensional.
by more than 62%. The permeameter shall be designed and
6.5.3 If a dual-ring permeameter is used, the plate corre-
operated such that permeant water flows upward or downward
sponding to the outflow end of the specimen (that is, bottom
through the test specimen. If upward flow operation is used,
plate for downward flow conditions) shall contain a ring
protect the top of the specimen from upward movement of soil
extendingoutwardfromtheplateinaperpendicularorientation
particles using a rigid porous element. Provisions may be
to the plate. The ring shall be constructed of stiff material (for
included along the sidewall of the permeameter to directly
example, steel, aluminum) of as thin as practical configuration
attach the device to the constant-head hydraulic system or the
to prevent deformation upon placement (for example, compac-
flow-measurement system, or both. Schematic diagrams of a
tion) of soil in the permeameter and not disrupt overall flow
typical permeameter cell are presented in Figs. 1 and 2 for
regime within the permeameter. It is recommended that the
single- and dual-ring rigid wall permeameter cells, respec-
diameter of the ring on the plate at the outflow end of the
tively.
specimen be no larger than 85% of the diameter of the
6.5.1 Top Plate—The top plate shall be constructed of a
permeameter cell. The diameter of the ring shall not vary by
rigid material that does not react adversely with the test
material or permeant water. The top plate may be sealed to the more than 2%. The ring shall be concentric to the permeame-
rigid-wallpermeametercellusinganO-ringorsimilarprevent- ter. The annular space between the ring and the permeameter
FIG. 1 Example Single-Ring Rigid Wall Permeameter (This schematic depicts a system with multiple inflow and outflow ports to the
specimen, which is not necessary to maintain desired head conditions, but can accommodate large flow volumes.)
D2434 − 22
FIG. 2 Example Dual-Ring Rigid Wall Permeameter
wall shall be at least as wide as the nominal particle size. The 6.5.5 Filter Paper—If necessary to prevent intrusion of soil
height of the ring shall be greater than the nominal particle into the pores of the porous end pieces, one or more sheets of
size.
filter paper shall be placed between the top and bottom porous
6.5.4 Porous End Pieces—The specimen shall be overlain
endpiecesandthespecimen.Thepapershallhaveanegligibly
andunderlainbyporousendpieces.Porousendpiecesshallbe
small hydraulic impedance. The requirements outlined in 8.1
used to distribute permeant water uniformly over the surfaces
shall be applied to verify that the impedance is sufficiently
of a test specimen (that is, areas perpendicular to the direction
small.
of flow) and shall not limit flow (that is, impedance to flow
6.6 Flexible Wall Permeameter (Method B)—An apparatus
shall be less through the end pieces than through the system).
shallbeprovidedinwhichthespecimenandporousendpieces,
Porous end pieces shall be constructed of a material that does
enclosed by a membrane sealed to the cap and base, are
not react with the specimen or the permeant water. Geosyn-
subjected to controlled fluid pressures.Aschematic diagram of
thetic materials such as geotextiles, geonets, and geotextile-
geonet composites (that is, geocomposites) may be used when a typical flexible wall permeameter cell is presented in Fig. 3.
flow through the system is less than the flow capacity of the
6.6.1 In order to facilitate gas removal, and thus saturation
geosynthetics. A flow distributor plate manufactured from
of the hydraulic system, four drainage lines leading to the
plastic also has been demonstrated to be effective. Holes in the
specimen, two each to the base and top caps, are recom-
flow distributor plate shall be large enough as to not inhibit
mended. The drainage lines shall be controlled by no-volume-
flow through the system. In addition, a metal mesh may be
change valves, such as ball valves, and shall be designed to
used. The top porous end piece shall have the same diameter
reduce the potential for presence of dead space (volumetric
(65% or better) as the specimen, and shall have sufficient
space in the system that does not contribute to hydraulic fluid
strength (that is, thickness) to prevent breaking. If a dual-ring
flow) in the lines.
permeameter is used, two porous end pieces are required at the
6.6.2 Top Cap and Base—An impermeable, rigid top cap
outflow end of the specimen due to the use of the plate
and base shall be used to support the specimen and provide for
containing the ring. The first porous end piece with a circular
transmission of permeant water to and from the specimen.The
shape shall have a diameter within 5% of the diameter of the
diameter or width of the top cap and base shall be equal to the
innerring.Thesecondporousendpiecewitharingshapeshall
diameter or width of the specimen to 65% or better.The base
have a width within 5% of the width of the annular space
shall prevent leakage, lateral motion, or tilting, and the top cap
between the inner collector ring and the permeameter cell.The
shallbedesignedtoreceivethepistonorextensometer,ifused,
endpiecesshallbefreefromclogging.Theflowcapacityofthe
such that the piston-to-top cap contact area is concentric with
porous end pieces shall be at least five times greater than that
the cap. The surfaces of the base and top cap that contacts the
of the specimen to be tested. The requirements outlined in 8.1
shall be applied to verify that this criterion is satisfied. membranetoformasealshallbesmoothandfreeofscratches.
D2434 − 22
FIG. 3 Example Flexible Wall Permeameter
6.6.3 Flexible Membrane—The flexible membrane used to used to distribute water uniformly over the surfaces of a test
encase the specimen shall provide reliable protection against specimen (that is, areas perpendicular to the direction of flow)
leakage. The membrane shall be carefully observed prior to and shall not limit flow (that is, flow through system shall be
use. If flaws or pinholes are evident, the membrane shall be
less than flow through end pieces). Porous end pieces shall be
discarded.Toreducethepotentialrestrainttothespecimen,the constructed of a material that does not react with the specimen
diameter or width of the non-stretched membrane shall be
or the permeant water. Geosynthetic materials such as
between 90 and 95% of that of the specimen. The membrane
geotextiles, geonets, and geotextile-geonet composites (that is,
shall be sealed to the specimen base and cap with rubber
geocomposites) may be used when flow through the system is
O-rings for which the unstressed, inside diameter or width is
less than the flow capacity of the geosynthetics. A flow
less than 95% of the diameter or width of the base and cap, or
distributor plate manufactured from plastic also has been
by other method that will produce an adequate seal.
de
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D2434 − 19 D2434 − 22
Standard Test MethodMethods for
Permeability of Granular Soils (Constant Head)Measurement
of Hydraulic Conductivity of Coarse-Grained Soils
This standard is issued under the fixed designation D2434; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope Scope*
1.1 This test method covers the determination of the coefficient of permeability by a constant-head method for the laminar flow
of water through granular soils. The procedure is to establish representativeThese test methods cover laboratory measurement of
the hydraulic conductivity (also referred to as values of the coeffıcient of permeability) of granular soils that may occur in natural
–7
depositswater-saturated coarse-grained soils (for example, sands and gravels) with ask placed in> 10 embankments, or when used
as base courses under pavements. In order to limit consolidation influences during testing, this procedure is limited to disturbed
granular soils containing not more than 10 % soil passing the 75-μm (No. 200) sieve.m/s. The test methods utilize low hydraulic
gradient conditions.
1.2 This standard describes two methods (A and B) for determining hydraulic conductivity of coarse-grained soils. Method A
incorporates use of a rigid wall permeameter and Method B incorporates the use of a flexible wall permeameter. A single- or
dual-ring rigid wall permeameter may be used in Method A. A dual-ring permeameter may be preferred over a single-ring
permeameter when adverse effects from short-circuiting of permeant water along the sidewalls of the permeameter (that is, prevent
sidewall leakage) are suspected by the user of this standard.
1.3 The test methods are used under constant head conditions.
1.4 The test methods are used under saturated soil conditions.
1.5 Water is used to permeate the test specimen with these test methods.
1.6 Units—The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided
for information only and are not considered No other units of measurement are included in this standard.
NOTE 1—Hydraulic conductivity has traditionally been reported in cm/s in the US, even though the official SI unit for hydraulic conductivity is m/s.
1.7 The observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice
D6026.
This test method is under the jurisdiction of ASTM Committee D18 on Soil and Rock and is the direct responsibility of Subcommittee D18.04 on Hydrologic Properties
and Hydraulic Barriers.
Current edition approved Oct. 1, 2019March 15, 2022. Published October 2019March 2022. Originally approved in 1965. Last previous edition approved in 20062019
as D2434–68(2006)D2434, which was withdrawn January 2015 and reinstated in October 2019. DOI: 10.1520/D2434-19.–19. DOI: 10.1520/D2434-22.
*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
D2434 − 22
1.8 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.
1.9 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.
2. Referenced Documents
2.1 ASTM Standards:
D653 Terminology Relating to Soil, Rock, and Contained Fluids
D2487 Practice for Classification of Soils for Engineering Purposes (Unified Soil Classification System)
D3740 Practice for Minimum Requirements for Agencies Engaged in Testing and/or Inspection of Soil and Rock as Used in
Engineering Design and Construction
D4753 Guide for Evaluating, Selecting, and Specifying Balances and Standard Masses for Use in Soil, Rock, and Construction
Materials Testing
D422D5101 Test Method for Particle-Size Analysis of SoilsMeasuring the Filtration Compatibility of Soil-Geotextile Systems
(Withdrawn 2016)
D4253D5716/D5716M Test Methods for Maximum Index Density and Unit Weight of Soils Using a Vibratory TableMethod for
Measuring the Rate of Well Discharge by Circular Orifice Weir
D6026 Practice for Using Significant Digits and Data Records in Geotechnical Data
D4254D6913/D6913M Test Methods for Minimum Index Density and Unit Weight of Soils and Calculation of Relative
DensityParticle-Size Distribution (Gradation) of Soils Using Sieve Analysis
3. Fundamental Test Conditions
3.1 The following ideal test conditions are prerequisites for the laminar flow of water through granular soils under constant-head
conditions:
3.1.1 Continuity of flow with no soil volume change during a test,
3.1.2 Flow with the soil voids saturated with water and no air bubbles in the soil voids,
3.1.3 Flow in the steady state with no changes in hydraulic gradient, and
3.1.4 Direct proportionality of velocity of flow with hydraulic gradients below certain values, at which turbulent flow starts.
3.2 All other types of flow involving partial saturation of soil voids, turbulent flow, and unsteady state of flow are transient in
character and yield variable and time-dependent coefficients of permeability; therefore, they require special test conditions and
procedures.
3. Terminology
3.1 Definitions:
3.1.1 For definitions of common technical terms in this standard, refer to Terminology D653.
3.1.2 hydraulic conductivity, k, n—(also referred to as coefficient of permeability or permeability) the rate of discharge of water
under laminar flow conditions through a unit cross-sectional area of porous medium under a unit hydraulic gradient and standard
temperature conditions (20°C).
3.1.3 hydraulic gradient, i, n—the change in total head (head loss, Δh) per unit distance (L) in the direction of fluid flow, in which
i = Δh ⁄L.
3.1.4 permeameter, n—the apparatus (cell) containing the test specimen in a hydraulic conductivity test.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
D2434 − 22
3.1.5 nominal particle size, n—the particle size corresponding to 75 % passing [that is, D ] per methods in Test Methods
D6913/D6913M.
4. Summary of Test Method
4.1 The standard includes methods for determining the hydraulic conductivity of free-draining soils (for example, sands and
gravels with low fines content) by permeating samples with water under constant head conditions. Multiple methods are presented
that include different permeameters (rigid wall, dual-ring rigid wall, and flexible wall). Different options for constant head systems
include reservoirs, Mariotte Bottle, and a flow pump.
5. Significance and Use
5.1 These test methods are used to measure one-dimensional vertical flow of water through initially saturated coarse-grained,
pervious (that is, free-draining) soils under an applied hydraulic gradient. Hydraulic conductivity of coarse-grained soils is used
in various civil engineering applications. These test methods are suitable for determination of hydraulic conductivity for soils with
–7
k > 10 m/s.
NOTE 2—Clean coarse-grained soils that are classified using Practice D2487-17 as GP, GW, SP, and SW can be tested using these test methods. Depending
on fraction and characteristics of fine-grained particles present in soils, these test methods may be suitable for testing other soil types with fines content
greater than 5 % (for example, GP-GC, SP-SM).
5.2 Coarse-grained soils are to be tested at a void ratio representative of field conditions. For engineered fills, compaction
specification can be used to provide target test conditions, whereas for natural soils, field testing of in-situ density can be used to
provide target test conditions.
5.3 Use of a dual-ring permeameter is included in these test methods in addition to a single-ring permeameter for the rigid wall
test apparatus. The dual-ring permeameter allows for reducing potential adverse effects of sidewall leakage on measured hydraulic
conductivity of the test specimens. The use of a plate at the outflow end of the specimen that contains a ring with a diameter smaller
than the diameter of the permeameter and the presence of two outflow ports (one from the inner ring, one from the annular space
between the inner ring and the permeameter wall) allows for separating the flow from the central region of the test specimen from
the flow near the sidewall of the permeameter.
NOTE 3—Sidewall leakage has been reported to have significant influence on flow conditions for coarse-grained soils due to presence of larger voids at
the boundary and higher void ratio in this region of the specimen. Three modifications that have been used to reduce this effect in rigid wall permeameters
include: i) placing a piping barrier (for example, caulk rings along every approximately 25-mm length of sidewall), ii) spreading a layer of bentonite and
petroleum jelly mixture along the entire surface area of the sidewall, and iii) using a closed-cell neoprene liner attached to the inside wall of the
permeameter.
5.4 Use of a flexible wall permeameter is included in these test methods in addition to the rigid wall permeameters. The flexible
wall permeameter reduces potential adverse effects of sidewall leakage on measured hydraulic conductivity of the test specimens
and allows for application of hydrostatic confining stress conditions on the specimen during the hydraulic conductivity test.
Confining stress allows for representing field conditions (that is, simulating stress states in the subgrade that may affect values of
k).
5.5 Darcy’s law is assumed to apply to the test conditions, flow is assumed to be laminar (see Note 4), and the hydraulic
conductivity is assumed to be considered independent of hydraulic gradient. The validity of these assumptions may be evaluated
by measuring the hydraulic conductivity of a specimen at three different hydraulic gradients. The discharge velocity (v = k × i) is
plotted against the applied hydraulic gradient. If the resulting relationship is linear and the measured hydraulic conductivity values
are similar (that is, within 25 %), then these assumptions are considered valid.
NOTE 4—Previous studies suggest that the limit between turbulent flow and laminar flow for soils occurs for Reynolds numbers between 1 and 10 (1 and
2) . A formulation for Reynolds number (and division for laminar and turbulent flow conditions) for flow through packed beds has been reported (3). The
formulation is presented for uniformly graded, spherical particles in Eq 1.
Dνρ
f
*
Re 5 (1)
μ 1 2 n
~ !
The last approved version of this historical standard is referenced on www.astm.org.boldface numbers in parentheses refer to a list of references at the end of this standard.
D2434 − 22
where:
Re* = Reynolds Number for packed bed flow,
D = granule or particle diameter (m),
v = superficial fluid velocity (that is, Darcy velocity) through bed (m/s),
ρ = fluid density (kg/m ),
f
μ = liquid viscosity (dynamic viscosity) (Pa s), and
n = porosity of bed (expressed as a ratio).
Provisions are provided in (3) for establishing equivalent particle diameter for use in this equation for nonuniform particle size distributions and
nonspherical particles.
NOTE 5—Using sufficiently low gradients has been demonstrated to be important for obtaining representative results. Hydraulic gradients less than 0.05
have been reported (4). Using a long test specimen (on the order of 1.5 m) has been reported as an effective method for achieving appropriately low
hydraulic gradients for materials with k > 0.01 m ⁄s.
NOTE 6—The quality of the result produced by this standard is dependent of the competence of the personnel performing it and the suitability of the
equipment and facilities used. Agencies that meet the criteria of Practice D3740 are generally considered capable of competent and objective testing,
sampling, inspection, etc. Users of this standard are cautioned that compliance with Practice D3740 does not in itself result in reliable values. Reliable
results depend on many factors; Practice D3740 provides a means of evaluating some of those factors.
6. Apparatus
6.1 Constant-Head Hydraulic System—The hydraulic system is used to apply, maintain, and measure heads and resulting hydraulic
gradients in a test. The hydraulic system mainly consists of reservoirs that hold water and associated piping, tubing, valves, and
connections. See Note 7. Pressure application setups also may be used to pressurize influent and effluent liquids. The system shall
be capable of maintaining constant hydraulic head to within 65 % or better and shall include means to measure the hydraulic
pressures to within the prescribed tolerances. In addition, the head loss must be held constant to 65 % or better and shall be
measured with instruments providing the same accuracy and readability or better. Large-scale specimens have high flow capacities
that may require specialized systems such as large reservoirs to provide adequate flow rates (see 8.1). Two alternate means of
achieving constant head conditions for k testing included in this standard are: a) Mariotte Bottle and b) use of a flow pump.
NOTE 7—Use of reservoirs with an overflow function (such as an outlet pipe or overflow along the perimeter of a level reservoir) that remains at a set
elevation for the duration of testing have been demonstrated to work well and will reduce the potential for changes in head during a test.
6.1.1 The head shall be measured with a rigid measuring tape, graduated reservoir, engineer’s scale, pressure gage, electronic
pressure transducer, or other device that has the resolution and accuracy required for the determination of head to the tolerances
provided above. Hydraulic heads shall be measured at points along the length of a test specimen using piezometers and from the
inflow and outflow elevations in the case of a rigid-wall permeameter. Hydraulic heads shall be measured from the inflow and
outflow elevations in the case of a flexible-wall permeameter. If measurements at inflow and outflow measurement locations are
to be used, the procedure specified in 8.1 shall be conducted to verify that negligible head loss occurs through the tubing and
system residing between the specimen and the inflow and outflow measurement locations. A general configuration for piezometers
is provided in Test Method D5716/D5716M. A porous filter is required for piezometers used in hydraulic conductivity tests to avoid
soils clogging the piping. A screen placed on the inside of the nipple assembly has been reported for such a filter (U.S. Army Corps
of Engineers (1980) Engineering and Design Laboratory Soils Testing, Engineer Manual no. 1110-2-1906).
6.1.2 System De-airing—The hydraulic system shall be designed to facilitate rapid and complete removal of free air bubbles from
flow lines. This removal can be accomplished, for example, by using tubing and ball valves that are large enough to prevent
entrapment of air bubbles, are large enough not to cause head losses as described in 8.1, and using fittings without pipe threads.
Placement of valve(s) at points of high elevation within the hydraulic system can facilitate venting of air from the system. If
de-aired water is used as permeant water, use a system with sufficient capacity to produce de-aired water for the test duration.
Recirculated permeant water shall not be used in the test.
6.2 Flow-Measurement System—The flow-measurement system is used to determine the amount of flow through a specimen
during a test. The measurement device shall allow for the measurement of the quantity of flow (inflow, outflow, or both inflow and
outflow, if selected for verification of flow conditions) over an interval of time to within 65 %. Flow-measurement system may
consist of a graduated accumulator, Mariotte bottle, electromagnetic flow meter, flow pump (if used to apply constant head), or
other mass/volume-measuring device that has the resolution and accuracy required to determine flow to the tolerances provided
above. In most cases, these devices are common to the hydraulic system.
6.2.1 De-airing and Dimensional Stability of the System—The flow-measurement system shall contain minimal dead space
(volumetric space in the system that does not contribute to hydraulic fluid flow) and shall be equipped to allow for complete and
D2434 − 22
rapid de-airing so that the system remains de-aired for the duration of testing. Dimensional stability of the system with respect to
changes in pressure shall be accomplished by using a stiff flow-measurement system that includes glass pipe or rigid metallic or
thermoplastic tubing.
6.3 Pressure Application System—The system (if used) for applying pressure on the coarse-grained soil specimen in the
permeameter shall allow for applying and controlling the pressure to within 65 % of the set value. For a rigid wall permeameter
(Method A), a vertical pressure application system is used. The vertical pressure application system may include a dead-weight
load application setup; a hydraulic load application system; or other system that allows for application of the desired level of
pressure to a specimen via the top of the specimen. The vertical effective stress on the test specimen (which is the difference
between the applied vertical pressure and the pore water pressure—provided a system to control pore water pressure is used) shall
be maintained to the desired value within 610 % of set value. For a flexible wall permeameter (Method B), a system for
pressurizing the permeameter cell shall be capable of applying and controlling the cell pressure to within 65 % of the set value.
The effective stress on the test specimen (which is the difference between the cell pressure and the pore water pressure) shall be
maintained to the desired value within 610 % of set value. The device for pressurizing the cell may consist of a reservoir connected
to the permeameter cell and partially filled with de-aired water, with the upper part of the reservoir connected to a compressed gas
supply or other source of pressure. A minimum of 2 to 3 m of water-filled distance within the apparatus between the pressurized
gas and the specimen is required (see Note 8). The gas pressure shall be controlled by a pressure regulator and measured by a
pressure gage, electronic pressure transducer, or other device capable of measuring to the prescribed tolerances. A hydraulic system
pressurized by dead weight acting on a piston or other pressure device capable of applying and controlling the permeameter cell
pressure within the tolerances prescribed in this section may be used.
NOTE 8—De-aired water is commonly used for the cell fluid to reduce the potential for diffusive air transport through the membrane into the specimen.
Other fluids that have low gas solubilities such as oils, are also acceptable, provided they do not react with components of the permeameter. Also, use
of a sufficiently long tube connecting the pressurized cell liquid to the cell helps to delay the appearance of air in the cell fluid and to reduce the flow
of dissolved air into the cell.
6.4 Permeameter—The permeameter shall consist of a cell for containing the test specimen and attached equipment that allow for
connecting the cell to the hydraulic system, the flow-measurement system, and the pressure application system (if applicable), as
well as provisions to support a specimen and to permeate the specimen. The permeameter shall consist of a cylindrical cell (rigid
for Method A, flexible for Method B), cover plate, base plate, and attachments to hold the components together without leakage
during a test. The diameter of the permeameter shall be determined based on the D (that is, the particle size corresponding to
95 % passing per methods in D6913/D6913M) of the soil to be tested. A permeameter diameter at least 10 times D is required.
The permeameter length shall be greater than 6 times D .
6.5 Rigid Wall Permeameter (Method A)—The permeameter shall consist of a rigid-wall cell into which the soil specimen to be
tested is placed and in which the test specimen is permeated. The permeameter shall be constructed of a rigid material such as steel,
aluminum, brass, or plastic that will not be damaged during placement/compression/compaction of the specimen in the cell. The
cross-sectional area along the direction of flow shall not vary by more than 62 % and the height shall not vary by more than 62 %.
The permeameter shall be designed and operated such that permeant water flows upward or downward through the test specimen.
If upward flow operation is used, protect the top of the specimen from upward movement of soil particles using a rigid porous
element. Provisions may be included along the sidewall of the permeameter to directly attach the device to the constant-head
hydraulic system or the flow-measurement system, or both. Schematic diagrams of a typical permeameter cell are presented in Figs.
1 and 2 for single- and dual-ring rigid wall permeameter cells, respectively.
6.5.1 Top Plate—The top plate shall be constructed of a rigid material that does not react adversely with the test material or
permeant water. The top plate may be sealed to the rigid-wall permeameter cell using an O-ring or similar preventing leakage or
the plate may be perforated and not sealed to the permeameter cell based on the design of the test setup. A sealed top plate is used
when the hydraulic or flow measurement system, or both, are connected to the top plate (or the permeameter cell) through
leak-proof ports or valves, whereas a perforated top plate is used when water is ponded directly above a specimen. The perforated
plate shall not impede flow. The procedure specified in 8.1 shall be conducted to verify that this criterion is satisfied. The top plate
shall be designed to distribute permeant water to the cross section of the specimen such that flow through the test specimen is
one-dimensional.
6.5.2 Base Plate—The bottom plate shall be constructed of a rigid material that does not react adversely with the test material or
permeant water. The base plate shall be sealed to the rigid-wall permeameter cell using an O-ring or similar preventing leakage.
The plate shall be designed to distribute permeant water to the cross section of the specimen such that flow through the test
specimen is one-dimensional.
D2434 − 22
FIG. 1 Constant-Head PermeameterExample Single-Ring Rigid Wall Permeameter (This schematic depicts a system with multiple inflow
and outflow ports to the specimen, which is not necessary to maintain desired head conditions, but can accommodate large flow vol-
umes.)
FIG. 2 Device for Evacuating and Saturating SpecimenExample Dual-Ring Rigid Wall Permeameter
6.5.3 If a dual-ring permeameter is used, the plate corresponding to the outflow end of the specimen (that is, bottom plate for
downward flow conditions) shall contain a ring extending outward from the plate in a perpendicular orientation to the plate. The
ring shall be constructed of stiff material (for example, steel, aluminum) of as thin as practical configuration to prevent deformation
upon placement (for example, compaction) of soil in the permeameter and not disrupt overall flow regime within the permeameter.
It is recommended that the diameter of the ring on the plate at the outflow end of the specimen be no larger than 85 % of the
diameter of the permeameter cell. The diameter of the ring shall not vary by more than 2 %. The ring shall be concentric to the
D2434 − 22
permeameter. The annular space between the ring and the permeameter wall shall be at least as wide as the nominal particle size.
The height of the ring shall be greater than the nominal particle size.
6.5.4 Porous End Pieces—The specimen shall be overlain and underlain by porous end pieces. Porous end pieces shall be used
to distribute permeant water uniformly over the surfaces of a test specimen (that is, areas perpendicular to the direction of flow)
and shall not limit flow (that is, impedance to flow shall be less through the end pieces than through the system). Porous end pieces
shall be constructed of a material that does not react with the specimen or the permeant water. Geosynthetic materials such as
geotextiles, geonets, and geotextile-geonet composites (that is, geocomposites) may be used when flow through the system is less
than the flow capacity of the geosynthetics. A flow distributor plate manufactured from plastic also has been demonstrated to be
effective. Holes in the flow distributor plate shall be large enough as to not inhibit flow through the system. In addition, a metal
mesh may be used. The top porous end piece shall have the same diameter (65 % or better) as the specimen, and shall have
sufficient strength (that is, thickness) to prevent breaking. If a dual-ring permeameter is used, two porous end pieces are required
at the outflow end of the specimen due to the use of the plate containing the ring. The first porous end piece with a circular shape
shall have a diameter within 5 % of the diameter of the inner ring. The second porous end piece with a ring shape shall have a
width within 5 % of the width of the annular space between the inner collector ring and the permeameter cell. The end pieces shall
be free from clogging. The flow capacity of the porous end pieces shall be at least five times greater than that of the specimen to
be tested. The requirements outlined in 8.1 shall be applied to verify that this criterion is satisfied.
6.5.5 Filter Paper—If necessary to prevent intrusion of soil into the pores of the porous end pieces, one or more sheets of filter
paper shall be placed between the top and bottom porous end pieces and the specimen. The paper shall have a negligibly small
hydraulic impedance. The requirements outlined in 8.1 shall be applied to verify that the impedance is sufficiently small.
6.6 Flexible Wall Permeameter (Method B)—An apparatus shall be provided in which the specimen and porous end pieces,
enclosed by a membrane sealed to the cap and base, are subjected to controlled fluid pressures. A schematic diagram of a typical
flexible wall permeameter cell is presented in Fig. 3.
6.6.1 In order to facilitate gas removal, and thus saturation of the hydraulic system, four drainage lines leading to the specimen,
two each to the base and top caps, are recommended. The drainage lines shall be controlled by no-volume-change valves, such
as ball valves, and shall be designed to reduce the potential for presence of dead space (volumetric space in the system that does
not contribute to hydraulic fluid flow) in the lines.
6.6.2 Top Cap and Base—An impermeable, rigid top cap and base shall be used to support the specimen and provide for
transmission of permeant water to and from the specimen. The diameter or width of the top cap and base shall be equal to the
diameter or width of the specimen to 65 % or better. The base shall prevent leakage, lateral motion, or tilting, and the top cap shall
be designed to receive the piston or extensometer, if used, such that the piston-to-top cap contact area is concentric with the cap.
The surfaces of the base and top cap that contacts the membrane to form a seal shall be smooth and free of scratches.
6.6.3 Flexible Membrane—The flexible membrane used to encase the specimen shall provide reliable protection against leakage.
The membrane shall be carefully observed prior to use. If flaws or pinholes are evident, the membrane shall be discarded. To reduce
the potential restraint to the specimen, the diameter or width of the non-stretched membrane shall be between 90 and 95 % of that
of the specimen. The membrane shall be sealed to the specimen base and cap with rubber O-rings for which the unstressed, inside
diameter or width is less than 95 % of the diameter or width of the base and cap, or by other method that will produce an adequate
seal.
NOTE 9—Membranes may be tested for flaws by placing them around a form sealed at both ends with rubber O-rings, subjecting them to a small air
pressure on the inside, and then dipping them into water and monitoring for presence of air bubbles emitting from the membrane.
6.6.4 Porous End Pieces—The specimen shall be overlain and underlain by porous end pieces. Porous end pieces shall be used
to distribute water uniformly over the surfaces of a test specimen (that is, areas perpendicular to the direction of flow) and shall
not limit flow (that is, flow through system shall be less than flow through end pieces). Porous end pieces shall be constructed of
a material that does not react with the specimen or the permeant water. Geosynthetic materials such as geotextiles, geonets, and
geotextile-geonet composites (that is, geocomposites) may be used when flow through the system is less than the flow capacity
of the geosynthetics. A flow distributor plate manufactured from plastic also has been demonstrated to be effective. Holes in the
flow distributor plate shall be large enough as to not inhibit flow through the system. In addition, a metal mesh may be used. The
top porous end piece shall have the same diameter (65 % or better) as the specimen, and shall have sufficient strength (that is,
thickness) to prevent breaking. The end pieces shall be free from clogging. The hydraulic conductivity of the porous end pieces
shall be at least 5 times greater than that of the specimen to be tested. The requirements outlined in 8.1 shall be applied to verify
that this criterion is satisfied.
D2434 − 22
FIG. 3 Permeability Test Data SheetExample Flexible Wall Permeameter
6.6.5 Filter Paper—If necessary to prevent intrusion of soil into the pores of the porous end pieces, one or more sheets of filter
paper shall be placed between the top and bottom porous end pieces and the specimen. The paper shall have a negligibly small
hydraulic impedance. The requirements outlined in 8.1 shall be applied to verify that the impedance is sufficiently small.
6.7 Permeameters, Specimen Length and Deformation Measurement—as shown in Fig. 1, shall have specimen cylinders with
minimum diameters approximately 8 or 12 times the maximum particle size in accordance with Table 1. The permeameter should
be fitted with: (shall be equipped 1) a porous disk or suitable reinforced screen at the bottom with a permeability greater than that
of the soil specimen, but with openings sufficiently small (not larger than 10 % finer size) to prevent movement of particles; (2)
manometer outlets for measuring the loss of head,for determination of axial h,length over a length, l, equivalent to at least the
diameter of the cylinder; (of 3) a porous disk or suitable reinforced screen with a spring attached to the top, or any other device,
for applying a light spring pressure of 22 to 45-N (5 to 10-lbf) total load, when a specimen during placement or during a test. The
length of a specimen shall be determined to the nearest 1 mm. The length of a specimen may be monitored by direct observation
through the cell wall using a cathetometer, camera setup, or other instrument that has the resolution and accuracy required for the
determination of length as prescribed above. The deformation (that is, change in length) of a specimen may also be monitored using
a deformation gage connected to the top plate is attached in place. This will hold the placement density and volume of soil without
significant change during the saturation of the specimen and the permeability testing to satisfy the requirement prescribed in above
D2434 − 22
a specimen or a deformation gage attached to a loading piston connected to the top plate above a specimen. The deformation can
be determined using a dial gage, LVDT, or other device that has the resolution and accuracy required for the determination of
deformation as prescribed above.3.1.1.
4.2 Constant-Head Filter Tank, as shown in Fig. 1, to supply water and to remove most of the air from tap water, fitted with
suitable control valves to maintain conditions described in 3.1.2.
NOTE 1—De-aired water may be used if preferred.
4.3 Large Funnels, fitted with special cylindrical spouts 25 mm (1 in.) in diameter for 9.5-mm ( ⁄8-in.) maximum size particles
and 13 mm ( ⁄2 in.) in diameter for 2.00-mm (No. 10) maximum size particles. The length of the spout should be greater than the
full length of the permeability chamber—at least 150 mm (6 in.).
6.8 Mariotte Bottle—Specimen Compaction Equipment—Compaction equipment as deemed desirable may be used. The
following are suggested: a vibrating tamper fitted with a tamping foot 51 mm (2 in.) in diameter; a sliding tamper with a tamping
foot 51 mm (2 in.) in diameter, and a rod for sliding weights of 100 g (0.25 lb) (for sands) to 1 kg (2.25 lb) (for soils with a large
gravel content), having an adjustable height of drop to 102 mm (4 in.) for sands and 203 mm (8 in.)The bottle assembly, if used,
shall be large enough to permit unimpeded water flow during permeation. The bottle assembly also shall be large enough to permit
unimpeded air flow through the bubble tube during permeation. The bottle design shall provide acceptable reading accuracy for
fluid levels (in relation to 6.1 forand 6.2soils with large gravel contents.).
4.5 Vacuum Pump or Water-Faucet Aspirator, for evacuating and for saturating soil specimens under full vacuum (see Fig. 2).
6.9 Manometer Tubes, Balances—with metric scales for measuring head of water.The balance shall be suitable for determining
the mass of a specimen. The balance shall be selected based on the guidelines provided in Specification D4753. The mass of
specimens shall be determined to the nearest 0.1 %.
6.10 Balance, Time Measurement Devices—of 2-kg (4.4-lb) capacity, sensitive to 1 g (0.002 lb).Devices to measure the duration
of each permeation trial, which shall be readable to 1 s, such as a clock with second hand or stopwatch (or equivalent), or both.
For trials that occur over a duration less than 60 s, a clock with both accuracy and readability to 0.1 s shall be used.
6.11 Scoop, Thermometer—with a capacity of about 100 g (0.25 lb) of soil.An instrument to determine temperature to an accuracy
of 61°C with a readability of 1°C or less.
6.12 Miscellaneous Apparatus—Vacuum Pump—Thermometers, clock with sweep second hand, 250-mL graduate, quart jar,
mixing pan, etc.A vacuum pump may be used to assist with de-airing of permeant water or saturation of specimens.
5. Sample
5.1 A representative sample of air-dried granular soil, containing less than 10 % of the material passing the 75-μm (No. 200) sieve
and equal to an amount sufficient to satisfy the requirements prescribed in 5.2 and 5.3, shall be selected by the method of
quartering.
5.2 A sieve analysis (see Method D422) shall be made on a representative sample of the complete soil prior to the permeability
test. Any particles larger than 19 mm ( ⁄4 in.) shall be separated out by sieving (Method D422). This oversize material shall not
be used for the permeability test, but the percentage of the oversize material shall be recorded.
NOTE 2—In order to establish representative values of coefficients of permeabilities for the range that may exist in the situation being investigated, samples
of the finer, average, and coarser soils should be obtained for testing.
5.3 From the material from which the oversize has been removed (see 5.2), select by the method of quartering, a sample for testing
equal to an amount approximately twice that required for filling the permeameter chamber.
D2434 − 22
7. Reagents
7.1 Permeant Water:
7.1.1 The permeant water is the liquid used to permeate the test specimen and is also the liquid used in backpressure saturation
of the specimen.
7.1.2 The type of permeant water shall be specified by the requestor. If no specification is made, potable tap water shall be used
for the permeant water. The type of permeant water utilized shall be indicated in the test data sheet/form.
8. PreparationVerification of Specimens System Flow
6.1 The size of permeameter to be used shall be as prescribed in Table 1.
6.2 Make the following initial measurements in centimetres or square centimetres and record on the data sheet (Fig. 3); the inside
diameter, D, of the permeameter; the length, L, between manometer outlets; the depth, H , measured at four symmetrically spaced
points from the upper surface of the top plate of the permeability cylinder to the top of the upper porous stone or screen temporarily
placed on the lower porous plate or screen. This automatically deducts the thickness of the upper porous plate or screen from the
height measurements used to determine the volume of soil placed in the permeability cylinder. Use a duplicate top plate containing
four large symmetrically spaced openings through which the necessary measurements can be made to determine the average value
for H . Calculate the cross-sectional area, A, of the specimen.
6.3 Take a small portion of the sample selected as prescribed in 5.3 for water content determinations. Record the weight of the
remaining air-dried sample (see 5.3), W , for unit weight determinations.
6.4 Place the prepared soil by one of the following procedures in uniform thin layers approximately equal in thickness after
compaction to the maximum size of particle, but not less than approximately 15 mm (0.60 in.).
6.4.1 For soils having a maximum size of 9.5 mm ( ⁄8 in.) or less, place the appropriate size of funnel, as prescribed in 4.3, in the
permeability device with the spout in contact with the lower porous plate or screen, or previously formed layer, and fill the funnel
with sufficient soil to form a layer, taking soil from different areas of the sample in the pan. Lift the funnel by 15 mm (0.60 in.),
or approximately the unconsolidated layer thickness to be formed, and spread the soil with a slow spiral motion, working from
the perimeter of the device toward the center, so that a uniform layer is formed. Remix the soil in the pan for each successive layer
to reduce segregation caused by taking soil from the pan.
6.4.2 For soils with a maximum size greater than 9.5 mm ( ⁄8 in.), spread the soil from a scoop. Uniform spreading can be obtained
by sliding a scoopful of soil in a nearly horizontal position down along the inside surface of the device to the bottom or to the
formed layer, then tilting the scoop and drawing it toward the center with a single slow motion; this allows the soil to run smoothly
from the scoop in a windrow without segregation. Turn the permeability cylinder sufficiently for the next scoopful, thus progressing
around the inside perimeter to form a uniform compacted layer of a thickness equal to the maximum particle size.
6.5 Compact successive layers of soil to the desired relative density by appropriate procedures, as follows, to a height of about
2 cm (0.8 in.) above the upper manometer outlet.
6.5.1 Minimum Density (0 % Relative Density)—Continue placing layers of soil in succession by one of the procedures described
in 6.4.1 or 6.4.2 until the device is filled to the proper level.
6.5.2 Maximum Density (100 % Relative Density):
6.5.2.1 Compaction by Vibrating Tamper—Compact each layer of soil thoroughly with the vibrating tamper, distributing the light
tamping action uniformly over the surface of the layer in a regular pattern. The pressure of contact and the length of time of the
vibrating action at each spot should not cause soil to escape from beneath the edges of the tamping foot, thus tending to loosen
the layer. Make a sufficient number of coverages to produce maximum density, as evidenced by practically no visible motion of
surface particles adjacent to the edges of the tamping foot.
6.5.2.2 Compaction by Sliding Weight Tamper—Compact each layer of soil thoroughly by tamping blows uniformly distributed
D2434 − 22
over the surface of the layer. Adjust the height of drop and give sufficient coverages to produce maximum density, depending on
the coarseness and gravel content of the soil.
6.5.2.3 Compaction by Other Methods—Compaction may be accomplished by other approved methods, such as by vibratory
packer equipment, where care is taken to obtain a uniform specimen without segregation of particle sizes (see Test Methods D4253
and D4254).
6.5.3 Relative Density Intermediate Between 0 and 100 %—By trial in a separate container of the same diameter as the
permeability cylinder, adjust the compaction to obtain reproducible values of relative density. Compact the soil in the permeability
cylinder by these procedures in thin layers to a height about 2.0 cm (0.80 in.) above the upper manometer outlet.
NOTE 3—In order to bracket, systematically and representatively, the relative density conditions that may govern in natural deposits or in compacted
embankments, a series of permeability tests should be made to bracket the range of field relative densities.
8.1 Preparation of Specimen for Permeability Test: Determination of System Flow Capacity—
6.6.1 Level the upper surface of the soil by placing the upper porous plate or screen in position and by rotating it gently back and
forth.Excessive head losses in the tubes, valves, porous end pieces, and filter papers (collectively described in Section 6) may limit
flow in the test system and lead to errors in measurements during permeation. System flow capacity shall be determined using the
actual permeant water that will be used in the test. The permeameter shall be assembled without a specimen and then water shall
be passed through the system. The hydraulic heads that will be used in testing a specimen shall be applied, and the rate of flow
shall be measured to within 65 %. The rate of flow shall be at least five times greater when no specimen is within the permeameter
than the rate of flow that is measured when a specimen is placed inside the permeameter with the same hydraulic heads applied.
Determination of system flow shall be conducted annually at a minimum. Retesting of the system flow capacity shall be conducted
subsequent to any change to the system configuration (for example, hardware setup, observed clogging during previous testing).
If five times flow of the system without a soil specimen (as compared to with a soil specimen) is not obtained, the permeameter
can still be used for testing if a) flow through the system without a soil specimen is greater than through the system with soil and
b) for head loss measurements taken at the reservoirs, a flow verification curve is developed for the system and used together with
the test results to determine a net change in head on the soil specimen, as presented in Annex A1.
6.6.2 Measure and record: the final height of specimen, H − H , by measuring the depth, H , from the upper surface of the
1 2 2
perforated top plate employed to measure H to the top of the upper porous plate or screen at four symmetrically spaced points
after compressing the spring lightly to seat the porous plate or screen during the measurements; the final weight of air-dried soil
used in the test (W − W ) by weighing the remainder of soil, W , left in the pan. Compute and record the unit weights, void ratio,
1 2 2
and relative density of the test specimen.
6.6.3 With its gasket in place, press down the top plate against the spring and attach it
...