1、Designation: D6766 12D6766 18Standard Test Method forEvaluation of Hydraulic Properties of Geosynthetic ClayLiners Permeated with Potentially Incompatible AqueousSolutions1This standard is issued under the fixed designation D6766; the number immediately following the designation indicates the year o
2、foriginal 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 laboratory measurement of both flu
3、x and hydraulic conductivity (also referred to as coeffcient ofpermeability) of geosynthetic clay liner (GCL) specimens permeated with chemical solutions and leachates utilizing a flexible wallpermeameter. For test measurement of index hydraulic properties of geosynthetic clay liners, refer to Test
4、Method D5887D5887/D5887M. For hydraulic conductivity compatibility of soils with aqueous chemical solutions and leachates, refer to Test MethodD7100.1.2 This test method may be utilized with GCL specimens that have a hydraulic conductivity less than or equal to 1 10 -55 mm/s s (1 10-33 cm/s).1.3 Thi
5、s test method is applicable to GCL products having geotextile backing(s). It is not applicable to GCL products withgeomembrane backing(s), geofilm backing(s)backing(s), or polymer coating backing(s).1.4 This test method provides measurements of flux and hydraulic conductivity under a prescribed set
6、of conditions, as an indextest, that can be used for manufacturing quality control. The flux and hydraulic conductivity values determined using this testmethod under the prescribed set of conditions is not considered to be representative of the in-service conditions of GCLs. However,the test method
7、allows the requester to establish a set of allows the requester to evaluate the hydraulic properties of a GCL withsite-specific or laboratory-prepared solution under different test conditions; thus, the test method also may be used to checkperformance or conformance, or both.1.5 The values stated in
8、 SI units are to be regarded as the standard, unless other units are specifically given. By tradition in U.S.practice, hydraulic conductivity is reported in centimeters per second, although the common SI units for hydraulic conductivityare meters per second.1.6 This standard does not purport to addr
9、ess all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine theapplicability of regulatory limitations prior to use.1.7 This international standar
10、d was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referen
11、ced Documents2.1 ASTM Standards:2D653 Terminology Relating to Soil, Rock, and Contained FluidsD854 Test Methods for Specific Gravity of Soil Solids by Water PycnometerD2216 Test Methods for Laboratory Determination of Water (Moisture) Content of Soil and Rock by MassD4439 Terminology for Geosyntheti
12、csD4753 Guide for Evaluating, Selecting, and Specifying Balances and Standard Masses for Use in Soil, Rock, and ConstructionMaterials Testing1 This test method is under the jurisdiction of ASTM Committee D35 on Geosynthetics and is the direct responsibility of Subcommittee D35.04 on Geosynthetic Cla
13、yLiners.Current edition approved July 1, 2012Feb. 1, 2018. Published September 2012February 2018. Originally approved in 2002. Last previous edition approved in 20092012as D6766D6766 12.09. DOI: 10.1520/D6766-12.10.1520/D6766-18.2 For referencedASTM standards, visit theASTM website, www.astm.org, or
14、 contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes hav
15、e been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official doc
16、ument.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1D5887D5887/D5887M Test Method for Measurement of Index Flux Through Saturated Geosynthetic Clay Liner SpecimensUsing a Flexible Wall PermeameterD7100 Test Method for Hydraulic Cond
17、uctivity Compatibility Testing of Soils with Aqueous SolutionsE145 Specification for Gravity-Convection and Forced-Ventilation Ovens3. Terminology3.1 Definitions:3.1.1 flux, nthe rate of discharge of liquid under laminar flow conditions through a unit cross-sectional area of a GCLspecimen at a stand
18、ard temperature condition (22 6 3C).3 C).3.1.2 geosynthetic clay liner (GCL), na factory-manufactured geosynthetic hydraulic barrier consisting of clay supported bygeotextiles, geomembranes, or a combination thereof, that are held together by needling, stitching, chemical adhesives, or othermethods.
19、3.1.3 hydraulic conductivity, k, nthe rate of discharge of liquid under laminar flow conditions through a unit cross-sectionalarea of a GCL specimen under a unit hydraulic gradient and standard temperature conditions (22 6 3C).3 C).3.1.3.1 DiscussionThe term coeffcient of permeability is often used
20、instead of hydraulic conductivity, but hydraulic conductivity is used exclusivelyin this test method. A more complete discussion of the terminology associated with Darcys law is given in the literature.33.1.4 index test, na test procedure that may contain bias, but may be used to establish comparabl
21、e results with respect to theproperty of interest.3.1.5 pore volume of flow, nthe cumulative quantity of flow into a test specimen divided by the volume of voids in thespecimen.3.2 For definitions of other terms used in this test method, see TerminologyTerminologies D653 and D4439.4. Significance an
22、d Use4.1 This test method applies to one-dimensional, laminar flow of water or other aqueous solutions, such as chemical solutions,landfill leachate, and contaminated water (here (from here on referred to as test liquid),“test liquid”), through saturated/hydratedGCL specimen that is consolidated and
23、 permeated under a prescribed or requested set of conditions.4.2 This test method can be performed to determine if the flux and/or hydraulic conductivity of a GCL specimen exceeds themaximum value stated by the manufacturer or required by the regulatory agencies, or both.4.2 It is assumed that Darcy
24、sThis test method assumes that Darcys law is valid and that the hydraulic conductivity isessentially unaffected by hydraulic gradient. The validity of DarcysDarcys law may be evaluated by measuring the hydraulicconductivity of the specimen at three different hydraulic gradients; if all measured valu
25、es are similar (within about 25 %), thenDarcys law may be taken as valid. However, when the hydraulic gradient acting on a test specimen is changed, the state of stresswill also change, and, if the specimen is compressible, the volume of the specimen will change. Thus, some change in hydraulicconduc
26、tivity may occur when the hydraulic gradient is altered, even in cases where Darcys law is valid.4.3 This test method provides tools for determining flux and hydraulic conductivity values for a given GCLunder the followingtwo different scenarios, which should be specified by the requester:4.3.1 Scen
27、ario 1Hydrated/Saturated 1 Hydrated/Saturated with Water Prior to Contact with Test LiquidThis scenariosimulates the field conditions where the GCL is well hydrated with water prior to contact with actual test liquid. It should be notedthat initial degree of saturation/hydration greatly affects the
28、hydraulic properties of a GCLproduct. The test has two phases: (Phase1) hydrate, saturate, consolidate, and permeate with water as Test Liquid 1, and (Phase 2) switch to permeation with test liquidas Test Liquid 2.4.3.2 Scenario 2Hydrated/Saturated 2 Hydrated/Saturated with Test Liquid (Worst Case)T
29、his scenario simulates the fieldconditions where the GCLis in contact with test liquid prior to being fully hydrated with water. It should be noted that this scenariomay result in higher flux and hydraulic conductivity values compared to Scenario 1, as chemicals present in test liquid may alterthe h
30、ydration and hydraulic properties of a GCL product.4.4 The apparatus used in this test method is commonly used to determine the hydraulic conductivity of soil specimens.However, flux values measured in this test are typically much lower than those commonly measured for most natural soils. It isessen
31、tial that the leakage rate of the apparatus in this test be less than 10 % of the flux.3 Olson, R. E. and Daniel, D. E. “Measurement of the Hydraulic Conductivity of Fine-Grained Soils,” Symposium on Permeability and Groundwater ContaminantTransport, ASTM STP 746, ASTM, 1981, pp. 1864.D6766 1825. Ap
32、paratus5.1 CompatibilityAll parts in contact with the test liquid(s) shall be checked/verified for long-term compatibility. This can beestablished either based on the available information or by in-house testing.5.2 Hydraulic SystemConstant head (MethodA), falling head (Methods B and C), or constant
33、 rate of flow (Method D) systemsmay be utilized provided they meet the criteria outlined as follows:5.2.1 Constant Head (Method A)The system must be capable of maintaining constant hydraulic pressures to within 65 % andshall include means to measure the hydraulic pressures to within the prescribed t
34、olerance. In addition, the head loss across theteststest specimen must be held constant to within 65 % and shall be measured with the same accuracy or better. Pressures shallbe measured by a pressure gage, electronic pressure transducer, or any other device of suitable accuracy.5.2.2 Falling Head (M
35、ethods B and C)The system shall allow for measurement of the applied head loss, thus hydraulicgradient, to within 65 %. In addition, the ratio of initial head loss divided by final head loss over an interval of time shall bemeasured such that this computed ratio is accurate to within 65 %. The head
36、loss shall be measured with a pressure gage,electronic pressure transducer, engineers scale, graduated pipette, or any other device of suitable accuracy. Falling head tests maybe performed with either a falling headwater and constant tailwater elevation (Method B) or a falling headwater and rising t
37、ailwaterelevation (Method C).5.2.3 Constant Rate of Flow (Method D)The system must be capable of maintaining a constant rate of flow through thespecimen to within +5 %. Flow measurement shall be by calibrated syringe, graduated pipette, or other device of suitable accuracy.The head loss across the s
38、pecimen shall be measured to an accuracy of 5 % or better using an electronic pressure transducer orother device of suitable accuracy. More information on testing with a constant rate of flow is given in the literature.45.2.4 System De-airingDe-AiringThe hydraulic system shall be designed to facilit
39、ate rapid and complete removal of freeair bubbles from flow lines.5.2.5 Back Pressure SystemThe hydraulic system shall have the capability to apply back-pressure back pressure to thespecimen to facilitate saturation. The system shall be capable of maintaining the applied back-pressure back pressure
40、throughoutthe duration of hydraulic conductivity measurements. The back-pressure back pressure system shall be capable of applying,controlling, and measuring the back-pressure back pressure to 5 % or better of the applied pressure. The back-pressure backpressure may be provided by a compressed gas s
41、upply (see Note 1), a deadweight dead weight acting on a piston, or any othermethod capable of applying and controlling the back-pressure back pressure to the tolerance prescribed in this paragraph.NOTE 1Application of gas pressure directly to a fluid will dissolve gas in the fluid. Any suitable tec
42、hnique, including separation of gas and liquidphases with a bladder, may be used to minimize dissolution of gas in the back-pressure back pressure fluid.5.3 Flow Measurement SystemBoth inflow and outflow volumes shall be measured unless the lack of leakage, continuity offlow, and cessation of consol
43、idation or swelling can be verified by other means. Flow volumes shall be measured by a graduatedaccumulator, graduated pipette, vertical standpipe in conjunction with an electronic pressure transducer, or other volume-measuring volume measuring device of suitable accuracy.5.3.1 Flow AccuracyRequire
44、d accuracy for the quantity of flow measured over an interval of time is 65 %.5.3.2 De-airingDe-Airing and Compliance of the SystemThe flow-measurement flow measurement system shall contain aminimum of dead space and be capable of complete and rapid de-airing. Compliance of the system in response to
45、 changes inpressure shall be minimized by using a stiff flow measurement system. Rigid tubing, such as metallic or rigid thermoplastic tubing,shall be used.5.3.3 Head LossesHead losses in the tubes, valves, porous end pieces, and filter paper may lead to error. To guard against sucherrors, the perme
46、ameter shall be assembled with no specimen inside and then the hydraulic system filled. If a constant or fallinghead test is to be used, the hydraulic pressures or heads that will be used in testing a specimen shall be applied, and the rate offlow measured with an accuracy of 5 % or better. This rat
47、e of flow shall be at least ten times greater than the rate of flow that ismeasured when a GCL specimen is placed inside the permeameter and the same hydraulic pressures or heads are applied. If aconstant rate of flow test is to be used, the rate of flow to be used in testing a specimen shall be sup
48、plied to the permeameter andthe head loss measured. The head loss without a specimen shall be less than 0.1 times the head loss when a GCL specimen ispresent.5.4 Permeant Interface Device (Bladder Accumulator)A permeant interface device shall be used when a hazardous/corrosiveor volatile test liquid
49、, or both, is to be used as the permeant. The permeant interface device shall contain the test liquid in a closedchamber and allow neither possible contamination of flow measurement and pressure systems nor potential release of chemicalspresent in the test liquid to the breathing air, while maintaining the desired test pressures. A schematic diagram of a typicalpermeant interface device is shown in Fig. 1. The device consistconsists of mainly a water chamber and a test liquid chamber,which are separated with a flexible bladder mem
