More D Comparative tests as directed in 5. 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.
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You are on page 1of 9 Search inside document Designation: D 00 Test Method for Determining the In-plane Flow Rate per Unit Width and Hydraulic Transmissivity of a Geosynthetic Using a Constant Head1 This standard is issued under the xed designation D ; 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. Scope 1. 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 eld conditions.
The values stated in parentheses are provided for information only. 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. Referenced Documents 2. Terminology 3. D 3. Current edition approved Feb. Published March Originally published as D Last previous edition D The static head is the sum of the elevation head and the pressure head.
D stress that is perpendicular to the surface on which the force acts. Summary of Test Method 4. 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 eld parameters as closely as possible.
Measurements may be repeated under increasing normal stresses selected by the user. Signicance and Use 5. Comparative tests as directed in 5. 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 2 Students 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. Apparatus 6. The individual components and accessories are as follows: 6. All seams between the bottom surface and sides of the base must be water tight and not inhibit in-plane ow 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.
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. 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.
For small discharge conditions, a narrow rectangular or triangular, V-notch weir may be warranted. The compressibility and thickness of the rubber layer should be selected such that it adequately represents the soil FIG. The material selected should not allow continuous ow 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. 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.
It will be necessary to establish calibration curves of volumetric ow 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. Sampling 7. For the laboratory sample, take a full width swatch of sufficient length along the roll edge so that the requirements of 7.
Cut the specimens such that the longer dimension is parallel to the geotextile direction for example, machine or cross-machine direction to be tested. For performance testing, the number of specimens to be tested is selected by the user. For performance testing, the number of specimens is selected by the user. Make the specimen length at least mm 14 in. Obtain the specimens with the longer dimension parallel to the geocomposite direction for example, machine or cross-machine direction to be tested.
The specimen length is at least mm 14 in. NOTE 1The actual length of the geocomposite specimen may have an inuence on the measured head losses and associated gradients; therefore, the specimen length of mm 14 in. In any case, always report the actual specimen length used. 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. Test Parameter Selection 8. In the absence of a specication, use rigid sub and superstrates to minimize the variables impacting the test results.
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.
NOTE 2Tests performed using site-specic 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. In the absence of a specication, use three gradients selected from the following values; 0. When specic eld conditions are not known, use one of the following recommended gradients as well as at least two lesser gradients. In the absence of a user or supplier specication, perform ow rate testing using a minimum of three applied normal stresses selected from the following values; 10, 25, 50, , and kPa 1.
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. This option should only be used when selected by the user or product specier.
Procedure 9. This precaution may not be warranted for test specimens that are rectangular in prole, placed between rigid surfaces and cut to t snugly against the sides of the base.
NOTE 3The elimination of leakage paths along the sides of the test specimen and along the loading tray adjacent to the upper surface of the specime merits close attention when testing geotextile materials. The user is cautioned of the relatively high variability see From this point forward, the specimen must be kept saturated at all times. If such ows are observed, re-seat or replace the test specimen as required. NOTE 4The use of deaired water is recommended for testing geotextiles and may be a consideration for test sections that include geotextiles where dissolved oxygen may inuence the test results.
Refer to Test Methods D for details regarding deaired water. The seating period selected should be based on long-term compression testing data at comparable stress levels. This is especially true for geosynthetics and sections including soils that exhibit compression creep or other long term deformation. For most specimens this length will be mm 12 in. Adjust the elevation of the water level in the reservoir box to change the system gradient.
Record the time required for at least an additional 0. If this time exceeds 15 min, record the quantity of ow collected at 15 min for use in calculations of the ow rate per unit width or hydraulic transmissivity, or both. Repeat the ow reading at least three times for each hydraulic gradient selected. Calculation Do not consider the length of the specimen that extends into the reservoir or weir, W 5 width of the specimen, m, and H 5 difference in total head across the specimen, m.
NOTE 5The calculation of the hydraulic transmissivity is applicable only for tests or specic regions of tests conducted under laminar ow conditions. To determine the ow regime, plot the ow rate per unit width versus the hydraulic gradient for each normal compressive stress see The data points for a given normal compressive stress form a straight line intersecting the origin if the test, or a region of the test, was conducted under laminar ow conditions.
The hydraulic transmissivity is equal to the slope of the straight line region on these plots see Appendix X1. Precision and Bias The design of the experiment, similar to that of Practice E , and a within-between analysis of the data, are given in an ASTM 5 Report Program details are provided in Table 1. The geonet was an HDPE geonet approximately 6-mm thick. The edge drain was a core-type tested without the geotextile wrap. Keywords Request RR:D Specimens Per No. Assemble the device with the calibration block in place of the geosynthetic specimen.
The inside height of the calibration block opening shall be equal to or greater than the uncompressed thickness of the geosynthetic specimen excluding adjacent soil or other components that are not intended to convey ow. The blocks are fabricated to provide an open channel for ow with a minimum of ow disruption across the width of the base.
The upstream and downstream ends of the blocks are open. The blocks should t tightly within the loading device specimen area.
ASTM D4716-01 Revision