ASTM D4716/D4716M-22

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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: D4716/D4716M − 20 D4716/D4716M − 22
Standard Test Method for
Determining the (In-plane) Flow Rate per Unit Width and
Hydraulic Transmissivity of a Geosynthetic Using a
Constant Head
This standard is issued under the fixed designation D4716/D4716M; 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
1.1 This test method covers the procedure for determining the flow rate per unit width within the manufactured plane of
geosynthetics under varying normal compressive stresses and a constant head. The test is intended primarily as an index test but
can be used also as a performance test when the hydraulic gradients and specimen contact surfaces are selected by the user to model
anticipated field conditions.
1.2 This test method is limited to geosynthetics that allow continuous in-plane flow paths to occur parallel to the intended direction
of flow.
1.3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each
system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used
independently of the other, and values from the two systems shall not be combined.
1.4 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.
1.5 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:
D4354 Practice for Sampling of Geosynthetics and Rolled Erosion Control Products (RECPs) for Testing
D4439 Terminology for Geosynthetics
D4491/D4491M Test Methods for Water Permeability of Geotextiles by Permittivity
D5092/D5092M Practice for Design and Installation of Groundwater Monitoring Wells
D5199 Test Method for Measuring the Nominal Thickness of Geosynthetics
D6574/D6574M Test Method for Determining the (In-Plane) Hydraulic Transmissivity of a Geosynthetic by Radial Flow
This test method is under the jurisdiction of ASTM Committee D35 on Geosynthetics and is the direct responsibility of Subcommittee D35.03 on Permeability and
Filtration.
Current edition approved June 1, 2020May 1, 2022. Published June 2020June 2022. Originally approved in 1995. Last previous edition approved in 20142020 as
D4716/D4716M – 14.D4716/D4716M – 20. DOI: 10.1520/D4716_D4716M-20.10.1520/D4716_D4716M-22.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D4716/D4716M − 22
D7361 Test Method for Accelerated Compressive Creep of Geosynthetic Materials Based on Time-Temperature Superposition
Using the Stepped Isothermal Method
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
3. Terminology
3.1 Definitions:
3.1.1 geocomposite, n—a product fabricated from any combination of geosynthetics with geotechnical materials or other
synthetics which is used in a geotechnical application. (D4439)
3.1.2 geonet, n—a geosynthetic consisting of integrally connected parallel sets of ribs overlying similar sets at various angles for
planar drainage of liquids or gases. (D4439)
3.1.3 geosynthetic, n—a planar product manufactured from polymeric material used with soil, rock, earth, or other geotechnical
engineering related material as an integral part of a man-made project, structure, or system. (D4439)
3.1.4 geotechnics, n—the application of scientific methods and engineering principalsprinciples to the acquisition, interpretation,
and use of knowledge of material of the earth’s crust to the solution of engineering problems.
3.1.4.1 Discussion—
Geotechnics embraces the fields of soil mechanics, rock mechanics, and many of the engineering aspects of geology, geophysics,
hydrology, and related sciences. (D4439)
3.1.5 geotextile, n—a permeable geosynthetic comprised solely of textiles. (D4439)
3.1.6 gravity flow, n—flow in a direction parallel to the plane of a geosynthetic driven predominantly by a difference in elevation
between the inlet and outflow points of a specimen.
3.1.6.1 Discussion—
The pressure at the outflow is considered to be atmospheric. (D4439)
3.1.7 head (static), n—the height above a standard datum of the surface of a column of water (or other liquid) that can be supported
by a static pressure at a given point. The static head is the sum of the elevation head and the pressure head. (D5092/D5092M)
3.1.8 hydraulic gradient, i, n—the loss of hydraulic head per unit distance of flow, dh/dL. (D4439)
2 −1
3.1.9 hydraulic transmissivity, θ (L T ),n—for a geosynthetic, the volumetric flow rate per unit width of specimen per unit
gradient in a direction parallel to the plane of the specimen.
3.1.9.1 Discussion—
“Transmissivity” is technically applicable only to saturated, laminar hydraulic flow conditions. (D4439)
3.1.10 in-plane flow, n—fluid flow confined to a direction parallel to the plane of a geosynthetic. (D4439)
3.1.10 index test, n—a test procedure that may contain known bias but which may be used to establish an order for a set of
specimens with respect to the property of interest. (D4439)
3.1.11 in-plane flow, n—fluid flow confined to a direction parallel to the plane of a geosynthetic. (D4439)
3.1.12 laminar flow, n—flow in which the head loss is proportional to the first power of the velocity. (D4439)
−2
3.1.13 normal stress (FL ), n—the component of applied stress that is perpendicular to the surface on which the force acts.
(D4439)
3.1.14 performance test, n—a test that simulates in the laboratory as closely as practical selected conditions experienced in the
field and which can be used in design. (D4439)
D4716/D4716M − 22
3.1.15 pressure flow, n—flow in a direction parallel to the plane of a geosynthetic driven predominantly by a differential fluid
pressure. (D4439)
3.1.16 turbulent flow, n—that type of flow in which any water particle may move in any direction with respect to any other particle,
and in which the head loss is approximately proportional to the second power of the velocity. (D4439)
3.1.17 For definitions of terms relating to geosynthetics, refer to Terminology D4439.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 steady flow, n—flow conditions that do not vary with time.
3.2.2 uniform flow, n—conditions where the flow area and the mean velocity in the direction of flow are constant.
4. Summary of Test Method
4.1 The flow rate per unit width is determined by measuring the quantity of water that passes through a test specimen in a specific
time interval under a specific normal stress and a specific hydraulic gradient. The hydraulic gradient(s) and specimen contact
surfaces are selected by the user either as an index test or as a performance test to model a given set of field parameters as closely
as possible. Measurements may be repeated under increasing normal stresses selected by the user.
4.1.1 The hydraulic transmissivity is the flow rate per unit width divided by the associated hydraulic gradient.
5. Significance and Use
5.1 This test method is intended either as an index test or as a performance test used to determine and compare the flow rate per
unit width of one or several candidate geosynthetics under specific conditions.
5.2 This test method may be used as an index test for acceptance testing of commercial shipments of geosynthetics, but caution
is advised since information on between-laboratory precision of this test method is incomplete. Comparative tests as directed in
5.2.1 may be advisable.
5.2.1 In case of a dispute arising from differences in reported test results when using this test method for acceptance testing of
commercial shipments, the purchaser and the supplier should first confirm that the tests were conducted using comparable test
parameters including specimen conditioning, normal stress, seating period, hydraulic gradient, test water temperature, etc., then
conduct comparative tests to determine if there is a statistical bias between their laboratories. Competent statistical assistance is
recommended for the investigation of bias. As a minimum, the two parties should take a group of test specimens that are as
homogenous as possible and that are formed from a lot of the material of the type in question. The test specimens should then be
randomly assigned in equal numbers to each laboratory for testing. The average results from the two laboratories should be
compared using the Student’s t-test for unpaired data and an acceptable probability level chosen by the two parties before the
testing is begun. If bias is found, either its cause must be found and corrected or the purchaser and supplier must agree to interpret
future test results in light of the known bias.
6. Apparatus
6.1 A schematic drawing of an assembly is shown in Fig. 1. The individual components and accessories are as follows:
6.1.1 Base—A sturdy metal base with smooth, flat bottom and sides capable of holding a test specimen of sufficient area and
thickness. All seams between the bottom surface and sides of the base must be watertight and not inhibit in-plane flow of water
through the specimen. For geotextile testing, all surfaces of the base in contact with the specimen shall be covered by a thin layer
of rubber material of low compressibility in order to ensure a tight seal.
6.1.2 Reservoir—A plastic, glass, or metal water reservoir extending the full width of the base. The height of the reservoir shall
be at least equal to the total length of the specimen. The reservoir shall have provision for maintaining a constant water level at
any of several elevations.
6.1.3 Loading Mechanism—Capable of sustaining a constant normal compressive stress on the specimen ranging from 10 kPa
D4716/D4716M − 22
FIG. 1 A Constant Head (In-Plane) Flow Rate Testing Device
[1.45 psi] to at least 500 kPa [70 psi] on a 305- by 305-mm [12- by 12-in.] 305 by 305 mm [12 by 12 in.] loaded area with an
accuracy of 61 %. The use of static weights, pneumatic bellows systems, or piston-applied stresses meeting the above conditions
may be considered sufficient for use in this test.
6.1.4 Outflow Weir—A plastic, glass, or metal reservoir extending the full width of the base at the outlet side of the specimen
having, at the opposite side, a rectangular weir at an elevation higher than the elevation of the upper surface of the specimen.
NOTE 1—The weir is used to sustain the steady, constant head condition on the outflow side of the specimen. For small discharge conditions, a narrow
rectangular or triangular,triangular V-notch weir may be warranted.
6.1.5 Outflow Collection—A catch trough extending the entire width of the base is used for collection and measurement of the
outflow from the specimen.
6.1.6 Rubber Substrate/Superstrate—Substrate/Superstrate (optional)—(optional) Rubber sheets cut to fit the base may be used
to model soil adjacent to the geosynthetic on one or both sides of the specimen if desired. The compressibility and thickness of
the rubber layer should be selected such that it adequately represents the soil being modeled. The material selected should not allow
continuous flow channels to exist through or around the rubber layer. These layers shall extend the entire length and width of the
base. The thickness of the rubber layers shall be at least twice the thickness of the geosynthetic specimen to be tested.
6.1.6.1 Compare the uncompressed thickness measured prior to use with the thickness measured at least one hour after use. If the
thickness decreases by 20 % or more, or if permanent indentations or damage are evident in the sheet, discard the sheet and retest
using a new sheet.
6.1.7 Thickness Monitoring Device—Device (optional)—(optional) In the form of a dial gauge and the like may be used to monitor
the change in the thickness of the geosynthetic specimen in the testing device under various applied normal stresses.
6.1.8 Manometers—Open manometers are located at the inlet and outlet ends of the specimen in the reservoir box and outflow
weir respectively (see Fig. 1). The manometer taps are placed at the same level as the base of the specimen as close to the specimen
ends as practical. Extend the manometers with clear tubing to a height at least as high as the maximum water level in the reservoir
box.
NOTE 2—The use of a pressure transducer(s) is recommended for measuring the pressure head when testing at hydraulic gradients less than 0.10. Use
a transducer(s) with an accuracy of 61 mm [60.04 in].in.].
6.1.9 Thermometer—For measuring the water temperature to an accuracy of 0.2 °C.
6.1.10 Calipers—For measuring the width of test specimens that are narrower than the standard 300-mm [12-in.] 300 mm [12 in.]
width with an accuracy of 1 mm.
6.2 In addition, the apparatus must not be the controlling agent for flow during the test. It will be necessary to establish calibration
curves of volumetric flow rate versus gradient for the apparatus alone using rigid, open channel substitutes (calibration blocks)
representing the range of geosynthetic thicknesses to be tested in order to establish compliance with this requirement. (See Annex
A1.)
D4716/D4716M − 22
7. Sampling
7.1 Lot Sample—Divide the product into lots, and for a lot to be tested take the lot sample as directed in Practice D4354.
7.2 Laboratory Sample—Consider the units in the lot sample as the units in the laboratory sample. For the laboratory sample, take
a full-width swatch of sufficient length along the roll edge so that the requirements of 7.3 – 7.5.3 can be met.
7.3 Test Specimens – Geotextiles—Geotextiles should be tested in accordance with Test Method D6574/D6574M.
7.4 Test Specimens – Geonets—For acceptance testing, remove two specimens from each unit in the laboratory sample with the
longer dimension parallel to the geonet direction (for example, machine or cross-machine direction) to be tested. The two test
specimens are normally taken one third in from each edge of the roll width sample swatch, but may be taken at two other locations
at the discretion of the user and noted in the report. For performance testing, the number of test specimens is selected by the user.
If one test specimen is requested for performance testing, it is normally taken from the center of the sample swatch, but may be
taken at two other locations at the discretion of the user and noted in the report.
7.4.1 Make the geonet specimen width 305 mm [12.0 in.]. Make the specimen length at least 350 mm [14 in.], or the length to
allow the specimen to extend into the reservoir and weir a distance of 25 mm [1 in.], whichever is greater.
7.5 Test Specimens – Geocomposites—For acceptance testing, remove two specimens from each unit in the laboratory sample with
the longer dimension parallel to the geocomposite direction (for example, machine or cross-machine direction) to be tested. The
two test specimens are normally taken one third in from each edge of the roll width sample swatch, but may be taken at two other
locations at the discretion of the user and noted in the report. For performance testing, the number of test specimens is selected
by the user. If one test specimen is requested for performance testing, it is normally taken from the center of the sample swatch,
but may be taken at two other locations at the discretion of the user and noted in the report.
7.5.1 For geocomposites manufactured with the full product width less than 305 mm [12.0 in.], the specimen width is equal to
the manufactured product width. The specimen length is at least 350 mm [14 in.], or the length to allow the specimen to extend
into the reservoir and weir a distance of 25 mm [1 in.], whichever is greater.
NOTE 3—The actual length of the geocomposite specimen may have an influence on the measured head losses and associated gradients; therefore, the
specimen length of 350 mm [14 in.] will be considered standard. In any case, always report the actual specimen length used.
7.5.2 For geocomposites manufactured with a full product width 305 mm [12.0 in.] or greater, the specimen width is 300 mm [12
in.] unless the product cannot be cut to width without altering the product structure.
7.5.3 For geocomposites consisting of two or more different geosynthetic components, determine the specimen dimensions for
each individual material in accordance with the applicable section,subsection, 7.3, 7.4, or 7.5.2. The minimum dimension of the
specimens shall then be dictated by the component requiring the largest minimum size. This requirement does not apply for
components sized per 7.5.1, which have manufactured widths less than 305 mm [12.0 in.].
8. Test Parameter Selection
8.1 Selection of Substrate and Superstrate:
8.1.1 Index Testing—For acceptance testing, the contact surfaces should be prescribed by the material specification. In the absence
of a specification, use rigid sub and superstrates to minimize the variables impacting the test results.
8.1.2 For performance testing, the nature of the material in contact with the geosynthetic in the field should be modeled. A rigid
platen on one or both sides of the specimen simulates similarly rigid surfaces (such as concrete walls or stiff geomembranes) where
intrusion into the geosynthetic openings or pore spaces is not anticipated. Where intrusion is expected (as is the case for a geotextile
in contact with soil or a geonet/geotextile/soil section) a layer of rubber membrane or representative soil may be placed between
the platen and the geosynthetic specimen.
NOTE 4—Tests performed using site-specific soils are recommended when the end use of the material is known. The long-term effect of soil clogging
should be considered when performing tests described in this test method.
D4716/D4716M − 22
8.2 Gradient Selection:
8.2.1 Index Testing—For acceptance testing, the test gradients should be prescribed by the material specification. In the absence
of a specification, use three gradients selected from the following values;values: 0.05, 0.10, 0.25, 0.50, and 1.0.
8.2.2 Performance Testing—Select a test hydraulic gradient that is appropriate for the end use of the material and for specific field
conditions. When specific field conditions are not known, use one of the following recommended gradients as well as at least two
lesser gradients.
8.2.2.1 A maximum hydraulic gradient of 1.0 is suggested for tests intended to model gravity flow conditions.
8.2.2.2 A maximum hydraulic gradient of 0.1 is suggested for tests intended to model pressure flow conditions.
8.3 Selection of the Applied Normal Compressive Stresses:
8.3.1 Index Testing—For acceptance testing, the applied normal compressive stress(es) should be prescribed by the material
specification. In the absence of a user or supplier specification, perform flow rate testing using a minimum of three applied normal
stresses selected from the following values;values: 10, 25, 50, 100, 250, and 500 kPa [1.45, 3.63, 7.26, 14.51, 36.28, and 72.55
psi].
8.3.2 For performance testing, select the minimum and maximum normal stress to be applied as to model the specific field
conditions. Perform the tests using a minimum of three applied normal stresses, selecting at least one value greater and one value
less than the known design stress value.
8.3.2.1 Where the design or maximum normal compressive stress for a particular application is known, it may be sufficient to test
the specimen under a single stress. This option should only be used when selected by the user or product specifier.
9. Procedure
9.1 Place the specimen substratum, if any, on the test device base. For test sections where the substratum consists of another
geosynthetic, the interface between the substratum and the base should be sealed to prevent water from flowing under the
substratum when this potential exists.
9.2 Trim the test specimen to the dimensions prescribed in 7.3 – 7.5 and then place the test specimen over the substratum, ensuring
that all wrinkles, folds, etc., are removed.
9.2.1 Seal the sides of the specimen parallel to the direction of flow by wrapping the test specimen in a thin sheet of low
compressibility plastic or rubber membrane, using a cast-in-place rubber or wax edge seal, or other measure (to prevent side
leakage). This precaution may not be warranted for test specimens that are rectangular in profile, placed between rigid surfaces,
and cut to fit snugly against the sides of the base.
NOTE 5—The elimination of leakage paths along the sides of the test specimen and along the loading tray adjacent to the upper surface of the specimen
merits close attention when testing geotextile materials. The user is cautioned of the relatively high variability (see 12.1) in the test results,results that
may be directly related to the laboratory’s ability to address these fugative flows.
9.3 Place the desired superstratum, if any, over the test specimen in a similar manner. For test sections where the superstratum
consists of another geosynthetic, the interface between the superstratum and the top plate should be sealed to prevent water from
flowing over the superstratum when this potential exists.
9.4 Seat the top plate (platen) on the test assembly applying a small seating stress of 5 to 10 kPa [0.73 to 1.45 psi]psi], and slowly
fill the reservoir with water allowing water to flow through the test specimen. From this point forward, the specimen must be kept
saturated at all times.
NOTE 6—For test devices or test sections, or both, where the test specimens are not placed into a loading tray that already contains water (which
allowallows for expulsion of trapped air from the test specimen), a pre-flush is recommended to expel air from the test specimen. This step entails raising
D4716/D4716M − 22
the water level in the reservoir to a gradient of approximately 0.5 and allowing the flow to continue until air bubbles no longer are visibly exiting the
weir end of the test specimen.
9.4.1 The test water should be maintained at 21 6 2 °C [70 6 4 °F] throughout the test duration.
9.4.2 Visually check for preferential flow paths along the boundaries of the test specimen. If such flows are observed, re-seat or
replace the test specimen as required.
NOTE 7—The use of deaired water is recommended for testing geotextiles and may be a consideration for test sections that include geotextiles where
dissolved oxygen may influence the test results. Refer to Test Methods D4491/D4491M for details regarding deaired water.
9.5 Seat the specimen under the minimum normal compressive stress for a minimum period of 15 min.
9.5.1 The minimum seating period suggested may not be sufficient for acceptance testing of geosynthetics that exhibit
time-dependent structural instability or other compressive response that significantly impacts the flow rate for stresses sustained
longer than 15 m
...