1、Designation: D6574/D6574M 131Standard Test Method forDetermining the (In-Plane) Hydraulic Transmissivity of aGeosynthetic by Radial Flow1This standard is issued under the fixed designation D6574/D6574M; the number immediately following the designation indicates theyear of original adoption or, in th
2、e 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.1NOTETable 1 was editorially inserted in Section 11.3 in March 2014.1. Scope1.1 This test method c
3、overs the procedure for determiningthe in-plane transmissivity of geosynthetics under varyingnormal compressive stresses using a radial flow apparatus. Thetest is intended to be an index test used primarily forgeotextiles, although other products composed of geotextilesand geotextile-type materials
4、may be suitable for testing withthis test method.1.2 This test method is based on the assumption that thetransmissivity of the geosynthetic is independent of orientationof the flow and is therefore limited to geosynthetics that havesimilar transmissivity in all directions and should not be usedfor m
5、aterials with oriented flow behavior.1.3 This test method has been developed specifically forgeosynthetics that have transmissivity values on the order of orless than2104m2/s. Consider using Test Method D4716 forgeosynthetics with transmissivity values higher than 2 104m2/s.1.4 The values stated in
6、either SI units or inch-pound unitsare to be regarded separately as standard. The values 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.1.5 This sta
7、ndard 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. Referenced Documents2.1
8、ASTM Standards:2D4354 Practice for Sampling of Geosynthetics and RolledErosion Control Products(RECPs) for TestingD4439 Terminology for GeosyntheticsD4716 Test Method for Determining the (In-plane) FlowRate per Unit Width and Hydraulic Transmissivity of aGeosynthetic Using a Constant HeadD5092 Pract
9、ice for Design and Installation of GroundwaterMonitoring Wells3. Terminology3.1 For definitions of terms relating to geosynthetics, referto Terminology D4439.3.2 Definitions:3.2.1 geosynthetic, na planar product manufactured frompolymeric material used with soil, rock, earth, or other geo-technical
10、engineering related material as an integral part of aman-made project, structure, or system. D44393.2.2 geotextile, na permeable geosynthetic comprisedsolely of textiles. D44393.2.3 gravity flow, nflow in a direction parallel to theplane of a geosynthetic driven predominantly by a difference ineleva
11、tion between the inlet and outflow points of a specimen.D44393.2.3.1 DiscussionThe pressure at the outflow is consid-ered to be atmospheric.3.2.4 head (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 give
12、n point. The static headis the sum of the elevation head and the pressure head. D50921This 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 July 1, 2013. Publis
13、hed July 2013. Originally approvedin 2000. Last previous edition approved in 2011 as D6574 00(2011). DOI:10.1520/D6574_D6574M-13E01.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume inform
14、ation, 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 States13.2.5 hydraulic gradient, i, s (D), nthe loss of hydraulichead per unit distance of flow, dH/dL. D44393.2.5.1 Discu
15、ssionThe gradient is not constant from pointto point in the direction of flow in the radial flow test. Thegradient (mathematically) varies with the inverse of the radialdistance from the center.3.2.6 hydraulic transmissivity, (L2T1), nfor ageosynthetic, the volumetric flow rate per unit width ofspec
16、imen per unit gradient in a direction parallel to the plane ofthe specimen. D44393.2.6.1 DiscussionTransmissivity is technically appli-cable only to saturated laminar flow hydraulic conditions.3.2.7 index test, na test procedure, which may contain aknown bias but which may be used to establish an or
17、der for aset of specimens with respect to the property of interest. D44393.2.8 in-plane flow, nfluid flow confined to a directionparallel to the plane of a geosynthetic. D44393.2.9 laminar flow, nflow in which the head loss isproportional to the first power of the velocity. D44393.2.10 normal stress
18、, (FL2), nthe component of appliedstress that is perpendicular to the surface on which the forceacts. D44393.2.11 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 s
19、econd power of the velocity. D44393.3 Definitions of Terms Specific to This Standard:3.3.1 steady flow, nhydraulic flow conditions that do notvary with time at any given point.3.3.2 uniform flow, nhydraulic flow conditions where thecross-sectional area and the mean velocity in the direction offlow a
20、re constant from point to point.4. Summary of Test Method4.1 The transmissivity is determined using a device whichtransmits the flow of water radially outward from the center ofa torus-shaped test specimen. The test method is performedwith a constant head under a specific normal stress selected byth
21、e user and may be repeated using several gradients and underincreasing normal stresses.4.2 The material property “hydraulic transmissivity” is tech-nically applicable only to the regions of tests where the flowrate is constant with gradient, that is, the laminar region of thetests.4.3 In the constan
22、t head radial flow test, the flow regime ischaracterized as nonuniform steady flow since the cross-sectional flow area and the hydraulic gradient vary from pointto point along any radial flow line while remaining constantwith time.5. Significance and Use5.1 This test method is an index test to estim
23、ate andcompare the in-plane hydraulic transmissivity of one or severalcandidate geosynthetics under specific gradient and stressconditions.5.2 This test method may be used for acceptance testing ofcommercial shipments of geosynthetics, but caution is advisedsince information about between-laboratory
24、 precision is in-complete. Comparative tests as directed in 5.2.1 are advisable.5.2.1 In case of a dispute arising from differences inreported test results when using this procedure for acceptanceof commercial shipments, the purchaser and the suppliershould first confirm that the tests have been con
25、ducted usingcomparable test parameters including specimen conditioning,normal stress, hydraulic system gradient, etc. Comparativetests then should be conducted to determine if there is astatistical bias between their laboratories. Competent statisticalassistance is recommended for the investigation
26、of bias. As aminimum, the two parties should take a group of test speci-mens that are as homogeneous as possible and that are formedfrom a lot of the material in question. The test specimensshould be assigned randomly to each laboratory for testing.The average results from the two laboratories shoul
27、d becompared using the Students t-test for unpaired data and anacceptable probability level chosen by the two parties beforetesting is begun. If bias is found, either its cause must be foundand corrected or the purchaser and supplier must agree tointerpret future test results in light of the known b
28、ias.6. Apparatus6.1 A schematic drawing of a typical constant head assem-bly is shown in Fig. 1. The individual components andaccessories are as follows:6.1.1 BaseThe bottom section of the apparatus should beconstructed of a sturdy metal or plastic plate with a smooth, flatcontact surface. The cente
29、r inlet hole shall be 50 mm 2 in.The outside dimension of the base must match or exceed theoutside diameter of the test specimen. A manometer tap shouldbe located in the sidewall of the inlet opening.6.1.2 Perimeter Containment/Outlet WeirAperimeter ringconcentric with the outside diameter of the te
30、st specimen withsufficient height to contain the tail water, such that thespecimen remains submerged under water at all times duringthe test. The containment ring should double as the overflowwier, with a beveled edge around the perimeter, with an outerconcentric collection trough for collection of
31、the overflow.Alternatively, the containment ring may include a rectangularoverflow weir at one location in the ring that is at least 2.5 cmwide with a beveled overflow plate.6.1.3 Loading PlatenA sturdy circular metal or plasticdisc with a smooth, flat contact surface. The outside diameterof the pla
32、ten should be 300 mm 12 in. The platen/specimendiameter establishes the outside diameter, Ro. The upper platenshould have a spherical chamber of an outside diametermatching the outside diameter of the inlet opening to facilitatecollection of any air bubbles that may collect at the specimeninlet. Thi
33、s chamber should be tapped at the apex to allowventing. This tap may also be connected to a manometer formeasurement of the inlet head.6.1.4 Rubber Base and Platen SurfacesA rubber mem-brane (sheet) material of buna, butyl, or neoprene rubber 1.5 to2.5 mm 116 to332 in. thick with a Shore A hardness
34、of 50 to80, cut to match the base and platen surfaces. The membranesmust be adhered to the base and platen surfaces.D6574/D6574M 13126.1.5 Loading MechanismAccurate to 61 % of the ap-plied loading and capable of sustaining a constant normalcompressive stress on the torus-shaped specimen within 62%su
35、stainable over the seating and testing period.The use of staticweights, a hydraulic, or a pneumatic ram meeting the aboveconditions may be considered sufficient for use in this testmethod.6.1.6 Constant Head Device (CHD)A device typicallyequipped with an inlet, two outlets, and an internal overfloww
36、eir or riser. The device should be sized to sustain steady flowconditions under the flow rates involved in the testing.6.1.6.1 Do not use the water level at the CHD to measurethe inlet head. The inlet head measurement shall be with themanometer tapped directly into the inlet chamber or the platentra
37、p.6.1.7 ManometersA manometer tap shall be installed inthe perimeter containment section to measure the tail headdirectly and, as detailed in the above sections, within the inletopening in the base to measure the inlet head directly. If arectangular weir is used (see 6.1.2), the tail head tap should
38、 belocated in the perimeter outflow trough at 90 to the weirlocation.6.1.7.1 The influence of the meniscus tension within themanometer sight tubes on the head measurements should bechecked by performing a test in accordance with this testmethod, then ramping the gradient back up to the maximumvalue
39、(see 10.8 and 10.9). The resulting degree of hyteresis inthe plot of flow rate versus gradient provides a measure of thesight tube accuracy. If the meniscus effect results in a differ-ence in flow rate values at a given gradient of more than 5 %,the sight tube accuracy should be improved by increasi
40、ng theinside diameter of the sight tubes, or by using tubes made ofglass instead of plastic, or both.6.1.8 Flowrate Measuring EquipmentEquipment that re-sults in a measurement event accuracy of 62 % of theassociated flowrate. Typically, the outflow is timed with astopwatch accurate to 0.1 s while be
41、ing collected in a conve-nient container and is then transferred to a 1000 mL Class Agraduated cylinder.6.1.9 Diefor cutting the test specimens, consisting of twoconcentric circular dies, the outer with a diameter of 300 mm12 in. and the inner with a diameter of 50 mm 2 in.6.1.10 Thickness Monitorin
42、g Device (Optional)In theform of a dial gauge and the like, accurate to 0.2 mm0.005 in., may be used to measure the change in the thicknessof the geosynthetic specimen in the device during the test.6.1.11 Test Waterthe water used for testing must bede-aired and filtered. The dissolved oxygen content
43、 should notexceed 6 ppm. The filter should have a maximum ratedopening size of 1-. The preferred test water temperature is 216 2C and shall be adhered to in the event of interlaboratorydisputes. For routine testing, maintain the test water at 21 65C.7. Sampling7.1 Lot SampleDivide the product into l
44、ots 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 swatch1minthemachine direction by the rollwidth.7.3 Test SpecimensRemove three specimens ra
45、ndomlyspaced along a diagonal extending across the swatch from eachlaboratory sample.7.3.1 Die cut the torus-shaped test specimens with anoutside diameter (Do) of 300 mm 12 in. and an insidediameter (Di) of 50 mm 2 in.7.3.2 The outside and inside diameters of the cut testspecimen should be within 62
46、 % of the dimensions specified.7.3.3 Examine the cut faces of the test specimen, both innerand outer diameter edges, checking for “pinching” of the fibersFIG. 1 A Radial Transmissivity Constant Head Testing DeviceD6574/D6574M 1313due to the cutting mechanism. Manually separate any pinchedareas caref
47、ully, restoring the cut edge of the material to the “asreceived” condition.8. Test Parameter Selection8.1 In the absence of a gradient (or gradients) prescribed bythe material specification, select a gradient from the followingvalues: 1.0, 0.50, 0.25, and 0.10.8.2 In the absence of normal compressiv
48、e stresses pre-scribed by the material specification, select a normal compres-sive stress from the following values: 5, 10, 25, and 50 kPa0.72, 1.45, 3.63, and 7.26 psi.8.3 In the absence of a seating period prescribed by thematerial specification, use a seating period of 15 min.9. Test Specimen Con
49、ditioning9.1 Pre-soak the test specimens in a closed container ofdeaired water for a minimum of 1 h.10. Test Procedure10.1 Set the elevation of the CHD, such that it is slightlyabove the outlet weir elevation, and fill the radial apparatuswith deaired water, covering the base surface.10.2 Place a conditioned test specimen carefully on thebase, laying the specimen down with a rolling motion into thewater, ensuring that all wrinkles, folds, etc., are removed. Bevigilant to expell any entrapped air that is visible
