1、Designation: D4716/D4716M 14Standard 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/D4716M; the number immediately following the designation indicates they
2、ear of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of lastreapproval. A superscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the procedure for determinin
3、gthe 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 selected b
4、y 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 either SI units or inch-pound unitsare to be regarded separately as standard. The valu
5、es stated ineach system may not be exact equivalents; therefore, eachsystem shall be used independently of the other. Combiningvalues from the two systems may result in non-conformancewith the standard.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with i
6、ts 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. Referenced Documents2.1 ASTM Standards:2D4354 Practice for Sampling of Geosynthetics and RolledErosion Control
7、 Products(RECPs) for TestingD4439 Terminology for GeosyntheticsD4491 Test Methods for Water Permeability of Geotextilesby PermittivityD5092 Practice for Design and Installation of GroundwaterMonitoring WellsD6574 Test Method for Determining the (In-Plane) Hydrau-lic Transmissivity of a Geosynthetic
8、by Radial FlowE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3. 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
9、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 used with soil, rock, earth, or
10、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 material of the earths crust to theso
11、lution 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 comprisedsolely of textiles. (D4439)3.1.6 g
12、ravity 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 (static), nthe height above a
13、 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 perunit distance of flow, dh/dL. (D4
14、439)1This test method is under the jurisdiction of ASTM Committee D35 onGeosynthetics and is the direct responsibility of Subcommittee D35.03 on Perme-ability and Filtration.Current edition approved Jan. 1, 2014. Published January 2014. Originallyapproved in 1995. Last previous edition approved in 2
15、013 as D4716 08 (2013).DOI: 10.1520/D4716_D4716M-14.2For referenced ASTM standards, visit the ASTM website, 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
16、 ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.1.9 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.3.1.9.1 Discuss
17、ion“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 containknown bias but wh
18、ich 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 is perpendicular to
19、 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 theplane of a geosynthetic
20、 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 velocity. (D4439)3.1.17 F
21、or 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 of flow are constant
22、.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 surfaces are select
23、ed 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 specific regions o
24、f 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 width of one or sever
25、al 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. Comparative testsas directed
26、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 parameters includin
27、g 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 bias. As a minimum, t
28、he 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 the two laboratorie
29、s 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 testresults in light of
30、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 seams between the botto
31、m 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 tight seal.6.1.2 R
32、eservoirA 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 Loading MechanismC
33、apable 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- byFIG. 1 A Constant Head (In-Plane) Flow Rate Testing DeviceD4716/D4716M 142305-mm 12- by 12-in. loaded area with an accuracy of 61%.The use of static weights,
34、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 the full width of the base at the outlet side of thespecimen having, at the opposite side, a rectangular
35、 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 weir may be warranted.6.1
36、.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 geosynthetic on one or both sides of
37、 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 layers shall extend the entire
38、 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 thickness decreases by 20 % o
39、r 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 specimen in the testingdevic
40、e 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 tothe specimen ends as p
41、ractical. 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 transducer(s) with an accuracy
42、 of 61mm60.04 in.6.1.9 ThermometerFor measuring the water temperatureto an accuracy of 0.2C.6.1.10 CalipersFor measuring the width of test specimensthat are narrower than the standard 300-mm 12-in. width withan accuracy of 1 mm.6.2 In addition, the apparatus must not be the controllingagent for flow
43、 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 geosyntheticthicknesses to be tested in order to establish compliance withthis requ
44、irement. (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 the units in the lotsample as the units in the laboratory sample. For the laboratorysample, take a full width swatch
45、 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 D6574.7.4 Test SpecimensGeonetsFor acceptance testing, re-move two specimens from each unit in the laboratory samplewith t
46、he 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 taken at twoother locations at the discretion of the user and noted in t
47、hereport. 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 other locations at thediscretion of the user and noted in the report.7.4
48、.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 distance of 25 mm 1 in., whichever is greater.7.5 Test SpecimensGeocompositesFor acceptancetesting, remove two specimens from ea
49、ch 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 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 performance testing, it is normally taken from thecen
