ASTM D5887-2008 459 Standard Test Method for Measurement of Index Flux Through Saturated Geosynthetic Clay Liner Specimens Using a Flexible Wall Permeameter.pdf

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1、Designation: D 5887 08Standard Test Method forMeasurement of Index Flux Through Saturated GeosyntheticClay Liner Specimens Using a Flexible Wall Permeameter1This standard is issued under the fixed designation D 5887; the number immediately following the designation indicates the year oforiginal adop

2、tion 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 an index test that coverslaboratory measurement

3、of flux through saturated geosyntheticclay liner (GCL) specimens using a flexible wall permeameter.1.2 This test method is applicable to GCL products havinggeotextile backing(s). It may not be applicable to GCL prod-ucts with geomembrane backing(s).1.3 This test method provides a measurement of flux

4、 undera prescribed set of conditions that can be used for manufactur-ing quality control. The test method can also be used to checkconformance. The flux value determined using this test methodis not considered to be representative of the in-service flux ofGCLs.1.4 The values stated in SI units are t

5、o be regarded as thestandard, unless other units are specifically given.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 t

6、he applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 653 Terminology Relating to Soil, Rock, and ContainedFluidsD 2216 Test Methods for Laboratory Determination of Wa-ter (Moisture) Content of Soil and Rock by MassD 4439 Terminology for GeosyntheticsD

7、 4753 Guide for Evaluating, Selecting, and SpecifyingBalances and Standard Masses for Use in Soil, Rock, andConstruction Materials TestingE 145 Specification for Gravity-Convection and Forced-Ventilation OvensE 691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test

8、Method3. Terminology3.1 Definitions:3.1.1 flux, nthe rate of discharge of water under laminarflow conditions through a unit cross-sectional area of a GCLspecimen.3.1.2 geosynthetic clay liner (GCL), na factory-manufactured geosynthetic hydraulic barrier consisting of claysupported by geotextiles, or

9、 geomembranes, or both, that areheld together by needling, stitching, or chemical adhesives.3.1.3 index test, na test procedure that may contain a bias,but that may be used to establish an order for a set of specimenswith respect to the property of interest.3.1.4 For definitions of other terms used

10、in this test method,see Terminology D 653 and Terminology D 4439.4. Summary of Test Method4.1 This test method involves permeation of a 100-mm(4-in.) diameter GCL test specimen. The specimen is set up ina flexible-wall permeameter, subjected to a total stress of 550kPa (80 psi) and a backpressure of

11、 515 kPa (75 psi) for a periodof 48 h. Flow is initiated using deionized water by raising thepressure on the influent side of the test specimen to 530 kPa (77psi). The flux is determined when inflow and outflow areapproximately equal (within 625 %).5. Significance and Use5.1 This test method yields

12、the flux of water through asaturated GCL specimen that is consolidated, hydrated, andpermeated under a prescribed set of conditions.5.2 This test method can be performed to determine if theflux of a GCL specimen exceeds the maximum value stated bythe manufacturer.5.3 This test method can be used to

13、determine the variationin flux within a sample of GCL by testing a number of differentspecimens.5.4 This test method does not provide a flux value to be useddirectly in design calculations.NOTE 1Flux for in-service conditions depends on a number of factors,including confining pressure, type of hydra

14、tion fluid, degree of hydration,1This test method is under the jurisdiction of ASTM Committee D35 onGeosynthetics and is the direct responsibility of Subcommittee D35.04 on Geosyn-thetic Clay Liners.Current edition approved July 1, 2008. Published July 2008. Originally approvedin 1995. Last previous

15、 edition approved in 2004 as D 5887 04.2For 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.1Copyright ASTM Intern

16、ational, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.degree of saturation, type of permeating fluid, and hydraulic gradient.Correlation between flux values obtained with this test method and fluxthrough GCLs subjected to in-service conditions has not been full

17、yinvestigated.5.5 This test method does not provide a value of hydraulicconductivity. Although hydraulic conductivity can be deter-mined in a manner similar to the method described in this testmethod, the thickness of the specimen is needed to calculatehydraulic conductivity. This test method does n

18、ot includeprocedures for measuring the thickness of the GCL nor of theclay component within the GCL.5.6 The apparatus used in this test method is commonlyused to determine the hydraulic conductivity of soil specimens.However, flux values measured in this test are typically muchlower than those commo

19、nly measured for most natural soils. Itis essential that the leakage rate of the apparatus used in thistest be less than 10 % of the flux.6. Apparatus6.1 Hydraulic System, constant head (Test Method A),falling head (Test Methods B and C), or constant rate of flow(Test Method D) systems may be utiliz

20、ed provided they meetthe criteria outlined as follows:6.1.1 Constant HeadThe system shall be capable ofmaintaining constant hydraulic pressures to within 65 % andshall include means to measure the hydraulic pressures towithin the prescribed tolerance. In addition, the head lossacross the test specim

21、en must be held constant to within 65%and shall be measured with the same accuracy or better.Pressures shall be measured by a pressure gage, electronicpressure transducer, or any other device of suitable accuracy.6.1.2 Falling HeadThe system shall allow for measure-ment of the applied head loss to w

22、ithin 65 % at any time. Inaddition, the ratio of initial head loss divided by final head lossover an interval of time shall be measured such that thiscomputed ratio is accurate to within 65 %. The head loss shallbe measured with a pressure gage, electronic pressure trans-ducer, engineers scale, grad

23、uated pipette, or any other deviceof suitable accuracy. Falling head tests may be performed witheither a constant tailwater elevation (Test Method B) or a risingtailwater elevation (Test Method C).6.1.3 Constant Rate of FlowThe system shall be capableof maintaining a constant rate of flow through th

24、e specimen towithin 65 %. Flow measurement shall be by calibrated sy-ringe, graduated pipette, or other device of suitable accuracy.The head loss across the specimens shall be measured to anaccuracy of 65 % using an electronic pressure transducer orother device of suitable accuracy. More information

25、 on testingwith a constant rate of flow is given in the literature.36.1.4 System De-AiringThe hydraulic system shall bedesigned to facilitate rapid and complete removal of free airbubbles from flow lines.6.1.5 Back Pressure SystemThe hydraulic system shallhave the capability to apply back pressure t

26、o the specimen tofacilitate saturation. The system shall be capable of maintain-ing the applied back pressure throughout the duration ofhydraulic conductivity measurements. The back pressure sys-tem shall be capable of applying, controlling, and measuringthe back pressure within 65 % of the applied

27、pressure. Theback pressure may be provided by a compressed gas supply, adeadweight acting on a piston, or any other method capable ofapplying and controlling the back pressure to the toleranceprescribed in this paragraph.NOTE 2Application of gas pressure directly to a fluid will dissolvegas in the f

28、luid. A variety of techniques are available to minimizedissolution of gas in the back pressure fluid, including separation of gasand liquid phases with a bladder and frequent replacement of the liquidwith de-aired water.6.2 Flow Measurement SystemBoth inflow and outflowvolumes shall be measured unle

29、ss the lack of leakage, conti-nuity of flow, and cessation of consolidation or swelling can beverified by other means. Flow volumes shall be measured by agraduated accumulator, graduated pipette, vertical standpipe inconjunction with an electronic pressure transducer, or othervolume-measuring device

30、 of suitable accuracy.6.2.1 Flow AccuracyRequired accuracy for the quantityof flow measured over an interval of time is 65%.6.2.2 De-Airing and Compliance of the SystemThe flow-measurement system shall contain a minimum of dead spaceand be capable of complete and rapid de-airing. Compliance ofthe sy

31、stem in response to changes in pressure shall beminimized by using a stiff flow measurement system. Rigidtubing, such as metallic or rigid thermoplastic tubing, shall beused.6.2.3 Head LossesHead losses in the tubes, valves, po-rous end pieces, and filter paper may lead to error. To guardagainst suc

32、h errors, the permeameter shall be assembled withno specimen inside and then the hydraulic system filled. If aconstant or falling head test is to be used, the hydraulicpressures or heads that will be used in testing a specimen shallbe applied, and the rate of flow measured with an accuracy of65 %. T

33、his rate of flow shall be at least ten times greater thanthe rate of flow that is measured when a specimen is placedinside the permeameter and the same hydraulic pressures orheads are applied. If a constant rate of flow test is to be used,the rate of flow to be used in testing a specimen shall besup

34、plied to the permeameter and the head loss measured. Thehead loss without a specimen shall be less than 0.1 times thehead loss when a specimen is present.6.3 Permeameter Cell Pressure SystemThe system forpressurizing the permeameter cell shall be capable of applyingand controlling the cell pressure

35、to within 65 % of the appliedpressure. However, the effective stress on the test specimenshall be maintained to the desired value with an accuracy of65 %. The device for pressurizing the cell may consist of areservoir connected to the permeameter cell and partially filledwith de-aired water, with th

36、e upper part of the reservoirconnected to a compressed gas supply or other source ofpressure (see Note 3). The gas pressure shall be controlled bya pressure regulator and measured by a pressure gage, elec-tronic pressure transducer, or any other device capable ofmeasuring to the prescribed tolerance

37、. A hydraulic system3Olson, H. W., Morin, R. H., and Nichols, R. W., “Flow Pump Applications inTriaxial Testing,” Symposium on Advanced Triaxial Testing of Soil and Rock, ASTMSTP 977, ASTM International, 1988, pp. 6881.D5887082pressurized by deadweight acting on a piston or any otherpressure device

38、capable of applying and controlling the per-meameter cell pressure to the tolerance prescribed in thisparagraph may be used.NOTE 3De-aired water is commonly used for the cell fluid tominimize potential for diffusion of air through the membrane into thespecimen. Other fluids, such as oils, which have

39、 low gas solubilities, arealso acceptable, provided they do not react with components of thepermeameter and the flexible membrane. Also, use of a long (approxi-mately 5 to 7 m) tube connecting the pressurized cell liquid to cell helpsto delay the appearance of air in the cell fluid and to reduce the

40、 flux ofdissolved air into the cell.6.4 Permeameter CellAn apparatus shall be provided inwhich the specimen and porous end pieces, enclosed by aflexible membrane sealed to the cap and base, are subjected tocontrolled fluid pressures.Aschematic diagram of a typical cellis shown in Fig. 1.6.4.1 The pe

41、rmeameter cell may allow for observation ofchanges in height of the specimen, either by observationthrough the cell wall using a cathetometer, or other instrument,or by monitoring of either a loading piston or an extensometerextending through the top plate of the cell bearing on the topcap and attac

42、hed to a dial indicator or other measuring device.The piston or extensometer should pass through a bushing andseal incorporated into the top plate and shall be loaded withsufficient force to compensate for the cell pressure acting overthe cross-sectional area of the piston where it passes throughthe

43、 seal. If deformations are measured, the deformation indi-cator shall be a dial indicator or cathetometer graduated to 0.3mm (0.01 in.) or better and having an adequate travel range.Any other measuring device meeting these requirements isacceptable.6.4.2 To facilitate gas removal, and thus saturatio

44、n of thehydraulic system, four drainage lines leading to the specimen,two each to the base and top cap, are recommended. Thedrainage lines shall be controlled by no-volume-change valves,such as ball valves, and shall be designed to minimize deadspace in the lines.6.5 Top Cap and BaseAn impermeable,

45、rigid top cap andbase shall be used to support the specimen and provide fortransmission of permanent liquid to and from the specimen.The diameter or width of the top cap and base shall be equal tothe diameter or width of the specimen 65 %. The base shallprevent leakage, lateral motion, or tilting, a

46、nd the top cap shallbe deigned to receive the piston or extensometer, if used, suchthat the piston-to-top cap contact area is concentric with thecap. The surface of the base and top cap that contacts themembrane to form a seal shall be smooth and free of scratches.6.6 Flexible MembranesThe flexible

47、membrane used toencase the specimen shall provide reliable protection againstleakage. The membrane shall be carefully inspected prior touse and if any flaws or pinholes are evident, the membraneshall be discarded. To minimize restraint of the specimen, thediameter or width of the unstretched membran

48、e shall bebetween 90 and 95 % of that of the specimen. The membraneshall be sealed to the specimen base and cap with rubberO-rings for which the unstressed, inside diameter or width isless than 90 % of the diameter or width of the base and cap, orby any other method that will produce an adequate sea

49、l.NOTE 4Membranes may be tested for flaws by placing them arounda form sealed at both ends with rubber O-rings, subjecting them to a smallair pressure on the inside, and then dipping them into water. If air bubblescome up from any point on the membrane, or if any visible flaws areobserved, the membrane shall be discarded.6.7 Porous End PiecesThe porous end pieces shall be ofsilicon carbide, aluminum oxide, or other material that is notattacked by the specimen or permanent liquid. The end piecesshall have plane and smooth surfaces and be free of cracks,chips, an