1、Designation: D4716 08 (Reapproved 2013)Standard Test 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 D4716; the number immediately following the designation indicates
2、the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the procedure for determ
3、iningthe flow rate per unit 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 select
4、ed by theuser to model anticipated 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 p
5、rovided forinformation only.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
6、prior to use.2. Referenced Documents2.1 ASTM Standards:2D4354 Practice for Sampling of Geosynthetics and RolledErosion Control Products(RECPs) for TestingD4439 Terminology for GeosyntheticsD4491 Test Methods for Water Permeability of Geotextilesby PermittivityD5092 Practice for Design and Installati
7、on of Ground WaterMonitoring WellsD6574 Test Method for Determining the (In-Plane) Hydrau-lic Transmissivity of a Geosynthetic by Radial Flow3. Terminology3.1 Definitions:3.1.1 geocomposite, na product fabricated from any com-bination of geosynthetics with geotechnical materials or othersynthetics w
8、hich is used in a geotechnical application.(D4439)3.1.2 geonet, na geosynthetic consisting of integrallyconnected parallel sets of ribs overlying similar sets at variousangles for planar drainage of liquids or gases. (D4439)3.1.3 geosynthetic, na planar product manufactured frompolymeric material us
9、ed with soil, rock, earth, or other geo-technical engineering related material as an integral part of aman-made project, structure, or system. (D4439)3.1.4 geotechnics, nthe application of scientific methodsand engineering principals to the acquisition, interpretation,and use of knowledge of materia
10、l of the earths crust to thesolution of engineering problems.3.1.4.1 DiscussionGeotechnics embraces the fields of soilmechanics, rock mechanics, and many of the engineeringaspects of geology, geophysics, hydrology, and relatedsciences. (D4439)3.1.5 geotextile, na permeable geosynthetic comprisedsole
11、ly of textiles. (D4439)3.1.6 gravity flow, nflow in a direction parallel to theplane of a geosynthetic driven predominantly by a difference 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. (D4439)3.1.7 head
12、 (static), nthe height above a standard datum ofthe surface of a column of water (or other liquid) that can besupported by a static pressure at a given point. The static headis the sum of the elevation head and the pressure head. (D5092)3.1.8 hydraulic gradient, i, nthe loss of hydraulic head peruni
13、t distance of flow, dh/dL. (D4439)3.1.9 hydraulic transmissivity, (L2T1),nfor ageosynthetic, the volumetric flow rate per unit width ofspecimen per unit gradient in a direction parallel to the plane ofthe specimen.1This test method is under the jurisdiction of ASTM Committee D35 onGeosynthetics and
14、is the direct responsibility of Subcommittee D35.03 on Perme-ability and Filtration.Current edition approved Jan. 1, 2013. Published January 2013. Originallyapproved in 1995. Last previous edition approved in 2008 as D4716 08. DOI:10.1520/D4716-08R13.2For referenced ASTM standards, visit the ASTM we
15、bsite, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United Sta
16、tes13.1.9.1 Discussion“transmissivity” is technically appli-cable only to saturated, laminar hydraulic flow conditions (seeAppendix X1). (D4439)3.1.10 in-plane flow, nfluid flow confined to a directionparallel to the plane of a geosynthetic. (D4439)3.1.11 index test, na test procedure that may conta
17、inknown bias but which may be used to establish an order for aset of specimens with respect to the property of interest.(D4439)3.1.12 laminar flow, nflow in which the head loss isproportional to the first power of the velocity. (D4439)3.1.13 normal stress (FL2), nthe component of appliedstress that
18、is perpendicular to the surface on which the forceacts. (D4439)3.1.14 performance test, na test that simulates in thelaboratory as closely as practical selected conditions experi-enced in the field and which can be used in design. (D4439)3.1.15 pressure flow, nflow in a direction parallel to theplan
19、e of a geosynthetic driven predominantly by a differentialfluid pressure. (D4439)3.1.16 turbulent flow, nthat type of flow in which anywater particle may move in any direction with respect to anyother particle, and in which the head loss is approximatelyproportional to the second power of the veloci
20、ty. (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, nflow conditions that do not vary withtime.3.2.2 uniform flow, nconditions where the flow area andthe mean velocity in the direction o
21、f 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 test specimen in aspecific time interval under a specific normal stress and aspecific hydraulic gradient. The hydraulic gradient(s) andspecimen contact
22、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. Measurements may berepeated under increasing normal stresses selected by the user.4.1.1 Hydraulic transmissivity should be determined onlyfor tests or for
23、 specific regions of tests that exhibit a linear flowrate per unit width versus gradient relationship, that is, laminarflow (see Appendix X1).5. Significance 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 wi
24、dth of one or several candidate geosynthetics underspecific conditions.5.2 This test method may be used as an index test foracceptance testing of commercial shipments of geosyntheticsbut caution is advised since information on between-laboratoryprecision of this test method is incomplete. Comparativ
25、e 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 for acceptancetesting of commercial shipments, the purchaser and the sup-plier should first confirm that the tests were conducted usingcomparable test
26、parameters including specimen conditioning,normal stress, seating period, hydraulic gradient, test watertemperature, etc., then conduct comparative tests to determineif there is a statistical bias between their laboratories. Compe-tent statistical assistance is recommended for the investigationof bi
27、as. 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 material of the type in question. Thetest specimens should then be randomly assigned in equalnumbers to each laboratory for testing. The average resultsfrom
28、the two laboratories should be compared using theStudents t-test for unpaired data and an acceptable probabilitylevel chosen by the two parties before the testing is begun. Ifbias is found, either its cause must be found and corrected orthe purchaser and supplier must agree to interpret future testr
29、esults 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 are 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 seam
30、s between the bottom surface and sidesof the base must be water tight and not inhibit in-plane flow ofwater through the specimen. For geotextile testing, 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
31、 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 least 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
32、 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 psi) on a 305- by305-mm (12- by 12-in.) loaded area with an accuracy of 61%.The use of static weights, pneumatic bellows systems, or pistonapplied stres
33、ses meeting the above conditions may be consid-ered sufficient for use in this test.FIG. 1 A Constant Head (In-Plane) Flow Rate Testing DeviceD4716 08 (2013)26.1.4 Outflow WeirA plastic, glass or metal reservoirextending the full width of the base at the outlet side of thespecimen having, at the opp
34、osite side, a rectangular weir at anelevation higher than the elevation of the upper surface of thespecimen.6.1.4.1 DiscussionThe weir is used to sustain the steady,constant head condition on the outflow side of the specimen.For small discharge conditions, a narrow rectangular ortriangular, V-notch
35、weir may be warranted.6.1.5 Outflow CollectionA catch trough extending theentire width of the base is used for collection and measurementof the outflow from the specimen.6.1.6 Rubber Substrate/Superstrate(optional) Rubbersheets cut to fit the base may be used to model soil adjacent tothe geosyntheti
36、c on one or both sides of the specimen ifdesired. The compressibility and thickness of the rubber layershould be selected such that it adequately represents the soilbeing modeled. The material selected should not allow con-tinuous flow channels to exist through or around the rubberlayer. These layer
37、s 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 to be tested.6.1.6.1 Compare the uncompressed thickness measuredprior to use with the thickness measured at least one hour afteruse. If the thic
38、kness decreases by 20 % or more, or ifpermanent indentations or damage are evident in the sheet,discard the sheet and retest using a new sheet.6.1.7 Thickness Monitoring Device(optional) In the formof a dial gauge and the like may be used to monitor the changein the thickness of the geosynthetic spe
39、cimen in the testingdevice under various applied normal stresses.6.1.8 ManometersOpen manometers are located at theinlet and outlet ends of the specimen in 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
40、 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.NOTE 1The use of a pressure transducer(s) is recommended formeasuring the pressure head when testing at hydraulic gradients less than0.10. Use a trans
41、ducer(s) with an accuracy of 61mm(6 0.04 in).6.2 In 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
42、blocks) representing the range of geosyntheticthicknesses 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 D4354.7.2 Laboratory SampleConsider
43、 the units in the lotsample as the units in the laboratory 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 D6574
44、.7.4 Test SpecimensGeonetsFor acceptance testing, 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
45、 of the roll width sample swatch, but may be taken 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
46、of thesample swatch, but may be taken at two other locations at thediscretion 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 thelength to allow the specimen to extend into the reservoir andweir a distan
47、ce of 25 mm (1 in.), whichever is greater.7.5 Test SpecimensGeocomposites For acceptancetesting, 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 spe
48、cimens are normally taken one thirdin from each edge 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 perfor
49、mance testing, it is normally taken from thecenter 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 305 mm (12.0 in.), the specimen width is equalto the manufactured product width. The specimen length is atleast 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 2The actual length of the geocomposite specimen
