1、Designation: D 4716 04Test Method forDetermining the (In-plane) Flow Rate per Unit Width andHydraulic Transmissivity of a Geosynthetic Using aConstant Head1This standard is issued under the fixed designation D 4716; the number immediately following the designation indicates the year oforiginal adopt
2、ion or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the procedure for determiningthe flow rate per u
3、nit width within the manufactured plane ofgeosynthetics under varying normal compressive stresses and aconstant head. The test is intended primarily as an index testbut can be used also as a performance test when the hydraulicgradients and specimen contact surfaces are selected by theuser to model a
4、nticipated field conditions.1.2 This test method is limited to geosynthetics that allowcontinuous in-plane flow paths to occur parallel to the intendeddirection of flow.1.3 The values stated in SI units are to be regarded as thestandard. The values stated in parentheses are provided forinformation o
5、nly.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenc
6、ed Documents2.1 ASTM Standards:2D 4354 Practice for Sampling of Geosynthetics for TestingD 4439 Terminology for GeosyntheticsD 4491 Test Methods for Water Permeability of Geotextilesby PermittivityD 6574 Test Method for Determining the In-Plane Hydrau-lic Transmissivity of a Geosynthetic by Radial F
7、low3. Terminology3.1 Definitions:3.1.1 geocomposite, na product fabricated from any com-bination of geosynthetics with geotechnical materials or othersynthetics which is used in a geotechnical application.(D 4439)3.1.2 geonet, na geosynthetic consisting of integrallyconnected parallel sets of ribs o
8、verlying similar sets at variousangles for planar drainage of liquids or gases. (D 4439)3.1.3 geosynthetic, na planar product manufactured frompolymeric material used with soil, rock, earth, or other geo-technical engineering related material as an integral part of aman-made project, structure, or s
9、ystem. (D 4439)3.1.4 geotechnics, nthe application of scientific methodsand engineering principals to the acquisition, interpretation,and use of knowledge of material of the earths crust to thesolution of engineering problems.3.1.4.1 DiscussionGeotechnics embraces the fields of soilmechanics, rock m
10、echanics, and many of the engineeringaspects of geology, geophysics, hydrology, and related sci-ences. (D 4439)3.1.5 geotextile, na permeable geosynthetic comprisedsolely of textiles. (D 4439)3.1.6 gravity flow, nflow in a direction parallel to theplane of a geosynthetic driven predominantly by a di
11、fference inelevation between the inlet and outflow points of a specimen.3.1.6.1 DiscussionThe pressure at the outflow is consid-ered to be atmospheric. (D 4439)3.1.7 head (static), nthe height above a standard datum ofthe surface of a column of water (or other liquid) that can besupported by a stati
12、c pressure at a given point. The static headis the sum of the elevation head and the pressure head.(D 5092)3.1.8 hydraulic gradient, i, nthe loss of hydraulic headper unit distance of flow, dh/dL. (D 4439)3.1.9 hydraulic transmissivity, u (L2T1), nfor a geosyn-thetic, the volumetric flow rate per un
13、it width of specimen perunit gradient in a direction parallel to the plane of thespecimen.3.1.9.1 Discussion“transmissivity” is technically appli-cable only to saturated, laminar hydraulic flow conditions (seeAppendix X1). (D 4439)1This test method is under the jurisdiction of ASTM Committee D35 onG
14、eosynthetics and is the direct responsibility of Subcommittee D35.03 on HydraulicProperties.Current edition approved July 1, 2004. Published August 2004. Originallyapproved in 1995. Last previous edition approved in 2003 as D 4716 03.2For referenced ASTM standards, visit the ASTM website, www.astm.o
15、rg, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.1.10 in-pl
16、ane flow, nfluid flow confined to a directionparallel to the plane of a geosynthetic. (D 4439)3.1.11 index test, na test procedure that may containknown bias but which may be used to establish an order for aset of specimens with respect to the property of interest.(D 4439)3.1.12 laminar flow, nflow
17、in which the head loss isproportional to the first power of the velocity. (D 4439)3.1.13 normal stress (FL2), nthe component of appliedstress that is perpendicular to the surface on which the forceacts. (D 4439)3.1.14 performance test, na test that simulates in thelaboratory as closely as practical
18、selected conditions experi-enced in the field and which can be used in design. (D 4439)3.1.15 pressure flow, nflow in a direction parallel to theplane of a geosynthetic driven predominantly by a differentialfluid pressure. (D 4439)3.1.16 turbulent flow, nthat type of flow in which anywater particle
19、may move in any direction with respect to anyother particle, and in which the head loss is approximatelyproportional to the second power of the velocity. (D 4439)3.1.17 For definitions of terms relating to geosynthetics,refer to Terminology D 4439.3.2 Definitions of Terms Specific to This Standard:3
20、.2.1 steady flow, nflow conditions that do not vary withtime.3.2.2 uniform flow, nconditions where the flow area andthe mean velocity in the direction of flow are constant.4. Summary of Test Method4.1 The flow rate per unit width is determined by measuringthe quantity of water that passes through a
21、test specimen in aspecific time interval under a specific normal stress and aspecific hydraulic gradient. The hydraulic gradient(s) andspecimen contact surfaces are selected by the user either as anindex test or as a performance test to model a given set of fieldparameters as closely as possible. Me
22、asurements may berepeated under increasing normal stresses selected by the user.4.1.1 Hydraulic transmissivity should be determined onlyfor tests or for specific regions of tests that exhibit a linear flowrate per unit width versus gradient relationship, that is, laminarflow (see Appendix X1).5. Sig
23、nificance and Use5.1 This test method is intended either as an index test or asa performance test used to determine and compare the flow rateper unit width of one or several candidate geosynthetics underspecific conditions.5.2 This test method may be used as an index test foracceptance testing of co
24、mmercial shipments of geosyntheticsbut caution is advised since information on between-laboratoryprecision of this test method is incomplete. Comparative testsas directed in 5.2.1 may be advisable.5.2.1 In case of a dispute arising from differences inreported test results when using this test method
25、 for acceptancetesting of commercial shipments, the purchaser and the sup-plier should first confirm that the tests were conducted usingcomparable test parameters including specimen conditioning,normal stress, seating period, hydraulic gradient, test watertemperature, etc., then conduct comparative
26、tests to determineif there is a statistical bias between their laboratories. Compe-tent statistical assistance is recommended for the investigationof bias. As a minimum, the two parties should take a group oftest specimens that are as homogenous as possible and that areformed from a lot of the mater
27、ial of the type in question. Thetest specimens should then be randomly assigned in equalnumbers to each laboratory for testing. The average resultsfrom the two laboratories should be compared using theStudents t-test for unpaired data and an acceptable probabilitylevel chosen by the two parties befo
28、re the testing is begun. Ifbias is found, either its cause must be found and corrected orthe purchaser and supplier must agree to interpret future testresults in light of the known bias.6. Apparatus6.1 A schematic drawing of an assembly is shown in Fig. 1.The individual components and accessories ar
29、e as follows:6.1.1 BaseA sturdy metal base with smooth flat bottomand sides capable of holding a test specimen of sufficient areaand thickness. All seams between the bottom surface and sidesof the base must be water tight and not inhibit in-plane flow ofwater through the specimen. For geotextile tes
30、ting, all surfacesof the base in contact with the specimen shall be covered by athin layer of rubber material of low compressibility in order toensure a tight seal.6.1.2 ReservoirA plastic, glass or metal water reservoirextending the full width of the base. The height of the reservoirshall be at lea
31、st equal to the total length of the specimen. Thereservoir shall have provision for maintaining a constant waterlevel at any of several elevations.6.1.3 Loading MechanismCapable of sustaining a con-stant normal compressive stress on the specimen ranging from10 kPa (1.45 psi) to at least 500 kPa (70
32、psi) on a 300- by300-mm (12- by 12-in.) loaded area with an accuracy of 61%.The use of static weights, pneumatic bellows systems, or pistonapplied stresses meeting the above conditions may be consid-ered sufficient for use in this test.6.1.4 Outflow WeirA plastic, glass or metal reservoirextending t
33、he full width of the base at the outlet side of thespecimen having, at the opposite side, a rectangular weir at anelevation higher than the elevation of the upper surface of thespecimen.6.1.5 DiscussionThe weir is used to sustain the steady,constant head condition on the outflow side of the specimen
34、.FIG. 1 A Constant Head (In-Plane) Flow Rate Testing DeviceD4716042For small discharge conditions, a narrow rectangular or trian-gular, V-notch weir may be warranted.6.1.6 Outflow CollectionA catch trough extending theentire width of the base is used for collection and measurementof the outflow from
35、 the specimen.6.1.7 Rubber Substrate/Superstrate(optional) Rubbersheets cut to fit the base may be used to model soil adjacent tothe geosynthetic on one or both sides of the specimen ifdesired. The compressibility and thickness of the rubber layershould be selected such that it adequately represents
36、 the soilbeing modeled. The material selected should not allow con-tinuous flow channels to exist through or around the rubberlayer. These layers shall extend the entire length and width ofthe base. The thickness of the rubber layers shall be at leasttwice the thickness of the geosynthetic specimen
37、to be tested.6.1.7.1 Compare the uncompressed thickness measuredprior to use with the thickness measured at least one hour afteruse. If the thickness decreases by 20 % or more, or ifpermanent indentations or damage are evident in the sheet,discard the sheet and retest using a new sheet.6.1.8 Thickne
38、ss Monitoring Device(optional) In the formof a dial gauge and the like may be used to monitor the changein the thickness of the geosynthetic specimen in the testingdevice under various applied normal stresses.6.1.9 ManometersOpen manometers are located at theinlet and outlet ends of the specimen in
39、the reservoir box andoutflow weir respectively (see Fig. 1). The manometer taps areplaced at the same level as the base of the specimen as close tothe specimen ends as practical. Extend the manometers withclear tubing to a height at least as high as the maximum waterlevel in the reservoir box.6.2 In
40、 addition, the apparatus must not be the controllingagent for flow during the test. It will be necessary to establishcalibration curves of volumetric flow rate versus gradient forthe apparatus alone using rigid, open channel substitutes(calibration blocks) representing the range of geosyntheticthick
41、nesses to be tested in order to establish compliance withthis requirement. (See Annex A1.)7. Sampling7.1 Lot SampleDivide the product into lots and for a lot tobe tested take the lot sample as directed in Practice D 4354.7.2 Laboratory SampleConsider the units in the lotsample as the units in the la
42、boratory sample. For the laboratorysample, take a full width swatch of sufficient length along theroll edge so that the requirements of 7.3-7.5.3 can be met.7.3 Test SpecimensGeotextilesGeotextiles should betested in accordance with Test Method D 6574.7.4 Test SpecimensGeonetsFor acceptance testing,
43、 re-move two specimens from each unit in the laboratory samplewith the longer dimension parallel to the geonet direction (forexample, machine or cross-machine direction) to be tested. Thetwo test specimens are normally taken one third in from eachedge of the roll width sample swatch, but may be take
44、n at twoother locations at the discretion of the user and noted in thereport. For performance testing, the number of test specimensis selected by the user. If one test specimen is requested forperformance testing, it is normally taken from the center of thesample swatch, but may be taken at two othe
45、r locations at thediscretion of the user and noted in the report.7.4.1 Make the geonet specimen width 300 mm (12 in.).Make the specimen length at least 350 mm (14 in.), or thelength to allow the specimen to extend into the reservoir andweir a distance of 25 mm (1 in.), whichever is greater.7.5 Test
46、SpecimensGeocomposites For acceptance test-ing, remove two specimens from each unit in the laboratorysample with the longer dimension parallel to the geocompositedirection (for example, machine or cross-machine direction) tobe tested. The two test specimens are normally taken one thirdin from each e
47、dge of the roll width sample swatch, but may betaken at two other locations at the discretion of the user andnoted in the report. For performance testing, the number of testspecimens is selected by the user. If one test specimen isrequested for performance testing, it is normally taken from thecente
48、r of the sample swatch, but may be taken at two otherlocations at the discretion of the user and noted in the report.7.5.1 For geocomposites manufactured with the full productwidth less than 300 mm (12 in.), the specimen width is equalto the manufactured product width. The specimen length is atleast
49、 350 mm (14 in.), or the length to allow the specimen toextend into the reservoir and weir a distance of 25 mm (1 in.),whichever is greater.NOTE 1The actual length of the geocomposite specimen may have aninfluence on the measured head losses and associated gradients; therefore,the specimen length of 350 mm (14 in.) will be considered standard. Inany case, always report the actual specimen length used.7.5.2 For geocomposites manufactured with a full productwidth 300 mm (12 in.) or greater, the specimen width is 300mm (12 in.) unless the produc
