1、Designation: D 6574 00 (Reapproved 2006)Standard Test Method forDetermining the (In-Plane) Hydraulic Transmissivity of aGeosynthetic by Radial Flow1This standard is issued under the fixed designation D 6574; the number immediately following the designation indicates the year oforiginal adoption or,
2、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 in-plane transmissivity
3、 of geosynthetics under varyingnormal compressive stresses using a radial flow apparatus. Thetest is intended to be an index test used primarily for geotex-tiles, although other products composed of geotextiles andgeotextile-type materials may be suitable for testing with thistest method.1.2 This te
4、st 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 materials with oriented flow behavior.1.3 This test method ha
5、s been developed specifically forgeosynthetics that have transmissivity values on the order of orless than 2 3 104m2/s. Consider using Test Method D 4716for geosynthetics with transmissivity values higher than 2 3104m2/s.1.4 The values stated in SI units are to be regarded as thestandard. The values
6、 given in parentheses are for informationonly.1.5 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 regul
7、atory limitations prior to use.2. Referenced 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 4716 Test Method for Determining the (In-plane) FlowRate pe
8、r Unit Width and Hydraulic Transmissivity of aGeosynthetic Using a Constant HeadD 5092 Practice for Design and Installation of GroundWater Monitoring Wells3. Terminology3.1 For definitions of terms relating to geosynthetics, referto Terminology D 4439.3.2 Definitions:3.2.1 geosynthetic, na planar pr
9、oduct 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 system. D 44393.2.2 geotextile, na permeable geosynthetic comprisedsolely of textiles. D 44393.2.3 gravity flow, nflow in
10、 a direction parallel to theplane of a geosynthetic driven predominantly by a difference inelevation between the inlet and outflow points of a specimen.D 44393.2.3.1 DiscussionThe pressure at the outflow is consid-ered to be atmospheric.3.2.4 head (static), nthe height above a standard datum ofthe s
11、urface 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.D 50923.2.5 hydraulic gradient, i, s (D), nthe loss of hydraulichead per unit distance of flow, dH/dL. D 44393.2.5.1 Discuss
12、ionThe 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, u (L2T1), nfor a geosyn-thetic, the volumetric flow rate per unit width of s
13、pecimen perunit gradient in a direction parallel to the plane of thespecimen. D 44393.2.6.1 DiscussionTransmissivity is technically appli-cable only to saturated laminar flow hydraulic conditions.1This test method is under the jurisdiction of ASTM Committee D35 onGeosynthetics and is the direct resp
14、onsibility of Subcommittee D35.03 on Perme-ability and Filtration.Current edition approved June 1, 2006. Published June 2006. Originallyapproved in 2000. Last previous edition approved in 2000 as D 6574 00.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer
15、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.3.2.7 index test, na test procedure, whi
16、ch may contain aknown bias but which may be used to establish an order for aset of specimens with respect to the property of interest.D 44393.2.8 in-plane flow, nfluid flow confined to a directionparallel to the plane of a geosynthetic. D 44393.2.9 laminar flow, nflow in which the head loss ispropor
17、tional to the first power of the velocity. D 44393.2.10 normal stress, (FL2), nthe component of appliedstress that is perpendicular to the surface on which the forceacts. D 44393.2.11 turbulent flow, nthat type of flow in which anywater particle may move in any direction with respect to anyother par
18、ticle and in which the head loss is approximatelyproportional to the second power of the velocity. D 44393.3 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
19、thecross-sectional area and the mean velocity in the direction offlow are 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 per
20、formedwith a constant head under a specific normal stress selected bythe 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 wi
21、th gradient, that is, the laminar region of thetests.4.3 In the constant 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 tim
22、e.5. Significance and Use5.1 This test method is an index test to estimate 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 geosynth
23、etics, but caution is advisedsince information about between-laboratory 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 purc
24、haser and the suppliershould first confirm that the tests have been conducted 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
25、. Competent statisticalassistance is recommended for the investigation 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 lab
26、oratory for testing.The average results from the two laboratories should 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 supp
27、lier must agree tointerpret future test results in light of the known bias.6. Apparatus6.1 A schematic drawing of a typical constant head assem-bly is shown in Fig. 1. The individual components andFIG. 1 A Radial Transmissivity Constant Head Testing DeviceD 6574 00 (2006)2accessories are as follows:
28、6.1.1 BaseThe bottom section of the apparatus should beconstructed of a sturdy metal or plastic plate with a smooth, flatcontact surface. The center 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 shoul
29、dbe located in the sidewall of the inlet opening.6.1.2 Perimeter Containment/Outlet WeirA perimeterring concentric with the outside diameter of the test specimenwith sufficient height to contain the tail water, such that thespecimen remains submerged under water at all times duringthe test. The cont
30、ainment ring should double as the overflowwier, with a beveled edge around the perimeter, with an outerconcentric collection trough for collection of 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
31、 beveled overflow plate.6.1.3 Loading PlatenA sturdy circular metal or plasticdisc with a smooth, flat contact surface. The outside diameterof the platen should be 300 mm (12 in). The platen/specimendiameter establishes the outside diameter, Ro. The upper platenshould have a spherical chamber of an
32、outside diametermatching the outside diameter of the inlet opening to facilitatecollection of any air bubbles that may collect at the specimeninlet. This 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
33、Base and Platen SurfacesA rubber mem-brane (sheet) material of Buna, Butyl, or Neopreney3rubber1.52.5 mm (116 332 in.) thick with a Shore A hardness of5080, cut to match the base and platen surfaces. The mem-branes must be adhered to the base and platen surfaces.6.1.5 Loading MechanismAccurate to 61
34、 % of the ap-plied loading and capable of sustaining a constant normalcompressive stress on the torus-shaped specimen within 62%sustainable 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 i
35、n this testmethod.6.1.6 Constant Head Device (CHD)A device typicallyequipped with an inlet, two outlets, and an internal overflowweir 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 me
36、asurethe inlet head. The inlet head measurement shall be with themanometer tapped directly into the inlet chamber or the platentrap.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 t
37、he inletopening in the base to measure the inlet head directly. If arectangular weir is used (see 6.1.2), the tail head tap should 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 measurement
38、s should bechecked by performing a test in accordance with this testmethod, then ramping the gradient back up to the maximumvalue (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 result
39、s in a differ-ence in flow rate values at a given gradient of more than 5 %,the sight tube accuracy should be improved by increasing 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 measur
40、ement event accuracy of 62 % of theassociated flowrate. Typically, the outflow is timed with astopwatch accurate to 0.1s while being 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 twoconcentri
41、c circular dies, the outer with a diameter of 300 mm(12 in.) and the inner with a diameter of 50 mm (2 in.).6.1.10 Thickness Monitoring Device (Optional)In theform of a dial gauge and the like, accurate to 0.2 mm(0.005 in.), may be used to measure the change in the thicknessof the geosynthetic speci
42、men in the device during the test.6.1.11 Test Waterthe water used for testing must bede-aired and filtered. The dissolved oxygen content 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 eve
43、nt of interlaboratorydisputes. For routine testing, maintain the test water at 21 65C.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 labora
44、tory sample. For the laboratorysample, take a swatch1minthemachine direction by the rollwidth.7.3 Test SpecimensRemove three specimens randomlyspaced 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
45、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 % 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 fibersdue
46、to the cutting mechanism. Manually separate any pinchedareas carefully, 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:
47、 1.0, 0.50, 0.25, and 0.10.8.2 In the absence of normal compressive stresses pre-scribed by the material specification, select a normal compres-sive stress from the following values: 5, 10, 25, and 50 kPa(0.72, 1.45, 3.63, and 7.26 psi).3Neoprene is a registered trademark.D 6574 00 (2006)38.3 In the
48、 absence of a seating period prescribed by thematerial specification, use a seating period of 15 min.9. Test Specimen Conditioning9.1 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 slightlyab
49、ove 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 within orbeneath the test specimen.10.2.1 If a specific side of the geosynthetic is to be tested,place this side facing the inlet opening.10.3 Place the loading platen with a “hinging” motion ontothe specim
