ASTM D4716-00
(Test Method)Test Method for Determining the (In-plane) Flow Rate per Unit Width and Hydraulic Transmissivity of a Geosynthetic Using a Constant Head
Test Method for Determining the (In-plane) Flow Rate per Unit Width and Hydraulic Transmissivity of a Geosynthetic Using a Constant Head
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 SI units are to be regarded as the standard. The values stated in parentheses are provided for information only.
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 and health practices and determine the applicability of regulatory limitations prior to use.
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Designation: D 4716 – 00
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 D 4716; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope 3.1.3 geosynthetic, n—a planar product manufactured from
polymeric material used with soil, rock, earth, or other geo-
1.1 This test method covers the procedure for determining
technical engineering related material as an integral part of a
the flow rate per unit width within the manufactured plane of
man-made project, structure, or system. (D 4439)
geosynthetics under varying normal compressive stresses and a
3.1.4 geotechnics, n—the application of scientific methods
constant head. The test is intended primarily as an index test
and engineering principals to the acquisition, interpretation,
but can be used also as a performance test when the hydraulic
and use of knowledge of material of the earth’s crust to the
gradients and specimen contact surfaces are selected by the
solution of engineering problems.
user to model anticipated field conditions.
3.1.4.1 Discussion—Geotechnics embraces the fields of soil
1.2 This test method is limited to geosynthetics that allow
mechanics, rock mechanics, and many of the engineering
continuous in-plane flow paths to occur parallel to the intended
aspects of geology, geophysics, hydrology, and related sci-
direction of flow.
ences. (D 4439)
1.3 The values stated in SI units are to be regarded as the
3.1.5 geotextile, n—a permeable geosynthetic comprised
standard. The values stated in parentheses are provided for
solely of textiles. (D 4439)
information only.
3.1.6 gravity flow, n—flow in a direction parallel to the
1.4 This standard does not purport to address all of the
plane of a geosynthetic driven predominantly by a difference in
safety concerns, if any, associated with its use. It is the
elevation between the inlet and outflow points of a specimen.
responsibility of the user of this standard to establish appro-
3.1.6.1 Discussion—The pressure at the outflow is consid-
priate safety and health practices and determine the applica-
ered to be atmospheric. (D 4439)
bility of regulatory limitations prior to use.
3.1.7 head (static), n—the height above a standard datum of
2. Referenced Documents
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
2.1 ASTM Standards:
is the sum of the elevation head and the pressure head.
D 4354 Practice for Sampling of Geosynthetics for Testing
(D 5092)
D 4439 Terminology for Geotextiles
3.1.8 hydraulic gradient, i, n—the loss of hydraulic head
D 4491 Test Methods for Water Permeability of Geotextiles
per unit distance of flow, dh/dL. (D 4439)
by Permittivity
2 −1
3.1.9 hydraulic transmissivity, u (L T ), n—for a geosyn-
3. Terminology
thetic, the volumetric flow rate per unit width of specimen per
unit gradient in a direction parallel to the plane of the
3.1 Definitions:
specimen.
3.1.1 geocomposite, n—a product fabricated from any com-
3.1.9.1 Discussion—“transmissivity” is technically appli-
bination of geosynthetics with geotechnical materials or other
cable only to saturated, laminar hydraulic flow conditions (see
synthetics which is used in a geotechnical application.
Appendix X1). (D 4439)
(D 4439)
3.1.10 in-plane flow, n—fluid flow confined to a direction
3.1.2 geonet, n—a geosynthetic consisting of integrally
parallel to the plane of a geosynthetic. (D 4439)
connected parallel sets of ribs overlying similar sets at various
3.1.11 index test, n—a test procedure that may contain
angles for planar drainage of liquids or gases. (D 4439)
known bias but which may be used to establish an order for a
set of specimens with respect to the property of interest.
This test method is under the jurisdiction of ASTM Committee D-35 on
(D 4439)
Geosynthetics and is the direct responsibility of Subcommittee D35.03 on Hydraulic
3.1.12 laminar flow, n—flow in which the head loss is
Properties.
proportional to the first power of the velocity. (D 4439)
Current edition approved Feb. 10, 2000. Published March 2000. Originally
−2
published as D 4716 – 95. Last previous edition D 4716 – 99.
3.1.13 normal stress (FL ), n—the component of applied
Annual Book of ASTM Standards, Vol 04.09.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
D 4716
stress that is perpendicular to the surface on which the force Student’s t-test for unpaired data and an acceptable probability
acts. (D 4439) level chosen by the two parties before the testing is begun. If
3.1.14 performance test, n—a test that simulates in the bias is found, either its cause must be found and corrected or
laboratory as closely as practical selected conditions experi- the purchaser and supplier must agree to interpret future test
enced in the field and which can be used in design. (D 4439) results in light of the known bias.
3.1.15 pressure flow, n—flow in a direction parallel to the
6. Apparatus
plane of a geosynthetic driven predominantly by a differential
6.1 A schematic drawing of an assembly is shown in Fig. 1.
fluid pressure. (D 4439)
3.1.16 turbulent flow, n—that type of flow in which any The individual components and accessories are as follows:
6.1.1 Base—A sturdy metal base with smooth flat bottom
water particle may move in any direction with respect to any
other particle, and in which the head loss is approximately and sides capable of holding a test specimen of sufficient area
and thickness. All seams between the bottom surface and sides
proportional to the second power of the velocity. (D 4439)
of the base must be water tight and not inhibit in-plane flow of
3.1.17 For definitions of terms relating to geosynthetics,
water through the specimen. For geotextile testing, all surfaces
refer to Terminology D 4439.
of the base in contact with the specimen shall be covered by a
3.2 Definitions of Terms Specific to This Standard:
thin layer of rubber material of low compressibility in order to
3.2.1 steady flow, n—flow conditions that do not vary with
ensure a tight seal.
time.
6.1.2 Reservoir—A plastic, glass or metal water reservoir
3.2.2 uniform flow, n—conditions where the flow area and
extending the full width of the base. The height of the reservoir
the mean velocity in the direction of flow are constant.
shall be at least equal to the total length of the specimen. The
4. Summary of Test Method
reservoir shall have provision for maintaining a constant water
4.1 The flow rate per unit width is determined by measuring level at any of several elevations.
the quantity of water that passes through a test specimen in a 6.1.3 Loading Mechanism—Capable of sustaining a con-
specific time interval under a specific normal stress and a stant normal compressive stress on the specimen ranging from
specific hydraulic gradient. The hydraulic gradient(s) and 10 kPa (1.45 psi) to at least 500 kPa (70 psi) on a 300- by
specimen contact surfaces are selected by the user either as an 300-mm (12- by 12-in.) loaded area with an accuracy of 61%.
index test or as a performance test to model a given set of field The use of static weights, pneumatic bellows systems, or piston
parameters as closely as possible. Measurements may be
applied stresses meeting the above conditions may be consid-
repeated under increasing normal stresses selected by the user. ered sufficient for use in this test.
4.1.1 Hydraulic transmissivity should be determined only
6.1.4 Outflow Weir—A plastic, glass or metal reservoir
for tests or for specific regions of tests that exhibit a linear flow extending the full width of the base at the outlet side of the
rate per unit width versus gradient relationship, that is, laminar specimen having, at the opposite side, a rectangular weir at an
flow (see Appendix X1). elevation higher than the elevation of the upper surface of the
specimen.
5. Significance and Use
6.1.5 Discussion—The weir is used to sustain the steady,
5.1 This test method is intended either as an index test or as
constant head condition on the outflow side of the specimen.
a performance test used to determine and compare the flow rate
For small discharge conditions, a narrow rectangular or trian-
per unit width of one or several candidate geosynthetics under
gular, V-notch weir may be warranted.
specific conditions.
6.1.6 Outflow Collection—A catch trough extending the
5.2 This test method may be used as an index test for
entire width of the base is used for collection and measurement
acceptance testing of commercial shipments of geosynthetics
of the outflow from the specimen.
but caution is advised since information on between-laboratory
6.1.7 Rubber Substrate/Superstrate—(optional) Rubber
precision of this test method is incomplete. Comparative tests
sheets cut to fit the base may be used to model soil adjacent to
as directed in 5.2.1 may be advisable.
the geosynthetic on one or both sides of the specimen if
5.2.1 In case of a dispute arising from differences in
desired. The compressibility and thickness of the rubber layer
reported test results when using this test method for acceptance
should be selected such that it adequately represents the soil
testing of commercial shipments, the purchaser and the sup-
plier 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. Compe-
tent 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 FIG. 1 A Constant Head (In-Plane) Flow Rate Testing Device
D 4716
being modeled. The material selected should not allow con- sample. Obtain the specimens with the longer dimension
tinuous flow channels to exist through or around the rubber parallel to the geocomposite direction (for example, machine
layer. These layers shall extend the entire length and width of or cross-machine direction) to be tested. For performance
the base. The thickness of the rubber layers shall be at least testing, the number of specimens is selected by the user.
twice the thickness of the geosynthetic specimen to be tested. 7.5.1 For geocomposites manufactured with the full product
6.1.7.1 Compare the uncompressed thickness measured width less than 300 mm (12 in.), the specimen width is equal
prior to use with the thickness measured at least one hour after to the manufactured product width. The specimen length is at
use. If the thickness decreases by 20 % or more, or if least 350 mm (14 in.), or the length to allow the specimen to
permanent indentations or damage are evident in the sheet, extend into the reservoir and weir a distance of 25 mm (1 in.),
discard the sheet and retest using a new sheet. whichever is greater.
6.1.8 Thickness Monitoring Device—(optional) In the form
NOTE 1—The actual length of the geocomposite specimen may have an
of a dial gauge and the like may be used to monitor the change
influence on the measured head losses and associated gradients; therefore,
in the thickness of the geosynthetic specimen in the testing
the specimen length of 350 mm (14 in.) will be considered standard. In
device under various applied normal stresses. any case, always report the actual specimen length used.
6.1.9 Manometers—Open manometers are located at the
7.5.2 For geocomposites manufactured with a full product
inlet and outlet ends of the specimen in the reservoir box and
width 300 mm (12 in.) or greater, the specimen width is 300
outflow weir respectively (see Fig. 1). The manometer taps are
mm (12 in.) unless the product cannot be cut to width without
placed at the same level as the base of the specimen as close to
altering the product structure.
the specimen ends as practical. Extend the manometers with
7.5.3 For geocomposites consisting of two or more different
clear tubing to a height at least as high as the maximum water
geosynthetic components, determine the specimen dimensions
level in the reservoir box.
for each individual material in accordance with the applicable
6.2 In addition, the apparatus must not be the controlling
section, 7.3, 7.4 or 7.5.2. The minimum dimension of the
agent for flow during the test. It will be necessary to establish
specimens shall then be dictated by the component requiring
calibration curves of volumetric flow rate versus gradient for
the largest minimum size. This requirement does not apply for
the apparatus alone using rigid, open channel substitutes
components sized per 7.5.1 which have manufactured widths
(calibration blocks) representing the range of geosynthetic
less than 300 mm (12 in.).
thicknesses to be tested in order to establish compliance with
this requirement. (See Annex A1.)
8. Test Parameter Selection
8.1 Selection of Substrate and Superstrate:
7. Sampling
8.1.1 Index Testing—For acceptance testing, the contact
7.1 Lot Sample—Divide the product into lots and for a lot to
surfaces should be prescribed by the material specification. In
be tested take the lot sample as directed in Practice D 4354.
the absence of a specification, use rigid sub and superstrates to
7.2 Laboratory Sample—Consider the units in the lot
minimize the variables impacting the test results.
sample as the units in the laboratory sample. For the laboratory
8.1.2 For performance testing, the nature of the material in
sample, take a full width swatch of sufficient length along the
contact with the geosynthetic in the field should be modeled. A
roll edge so that the requirements of 7.3-7.5.3 can be met.
rigid platen on one or both sides of the specimen simulates
7.3 Test Specimens—Geotextiles—For acceptance testing,
similarly rigid surfaces (such as concrete walls or stiff
remove three specimens from each laboratory sample which
geomembranes) where intrusion into the geosynthetic openings
are spaced along a diagonal extending across the swatch. Cut
or pore spaces is not anticipated. Where intrusion is expected
the specimens such that the longer di
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