1、Designation: D 5856 95 (Reapproved 2007)Standard Test Method forMeasurement of Hydraulic Conductivity of Porous MaterialUsing a Rigid-Wall, Compaction-Mold Permeameter1This standard is issued under the fixed designation D 5856; the number immediately following the designation indicates the year ofor
2、iginal adoption or, 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 laboratory measurement of thehydraul
3、ic conductivity (also referred to as coeffcient of per-meability) of laboratory-compacted materials with a rigid-wall,compaction-mold permeameter.1.2 This test method may be used with laboratory-compacted specimens that have a hydraulic conductivity lessthan or equal to 1 3 105m/s. The hydraulic con
4、ductivity ofcompacted materials that have hydraulic conductivities greaterthan 1 3 105m/s may be determined by Test Method D 2434.1.3 The values stated in SI units are to be regarded as thestandard, unless other units are specifically given. By traditionin U.S. practice, hydraulic conductivity is re
5、ported in centime-tres per second, although the common SI units for hydraulicconductivity are metres per second.1.4 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 saf
6、ety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 653 Terminology Relating to Soil, Rock, and ContainedFluidsD 698 Test Methods for Laboratory Compaction Character-istics of Soil Using Standard Effort (12,400
7、 ft-lbf/ft3(600kN-m/m3)D 854 Test Methods for Specific Gravity of Soil Solids byWater PycnometerD 1557 Test Methods for Laboratory Compaction Charac-teristics of Soil Using Modified Effort (56,000 ft-lbf/ft3(2,700 kN-m/m3)D 2216 Test Methods for Laboratory Determination of Wa-ter (Moisture) Content
8、of Soil and Rock by MassD 2434 Test Method for Permeability of Granular Soils(Constant Head)D 4753 Guide for Evaluating, Selecting, and SpecifyingBalances and Standard Masses for Use in Soil, Rock, andConstruction Materials TestingD 5084 Test Methods for Measurement of Hydraulic Con-ductivity of Sat
9、urated Porous Materials Using a FlexibleWall PermeameterE 145 Specification for Gravity-Convection and Forced-Ventilation Ovens3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 fluxquantity of flow per unit area per unit time.3.1.2 hydraulic conductivity, kthe rate of discharge
10、ofwater under laminar flow conditions through a unit cross-sectional area of a porous medium under a unit hydraulicgradient and standard temperature conditions (20C).3.1.2.1 DiscussionThe term coeffcient of permeability isoften used instead of hydraulic conductivity, but hydraulicconductivity is use
11、d exclusively in this test method. A morecomplete discussion of the terminology associated with Dar-cys law is given in the literature3.3.1.3 pore volume of flowthe cumulative quantity ofoutflow from a test specimen divided by the volume of porespace in the specimen.3.1.4 For definitions of other te
12、rms used in this test methodsee Terminology D 653.4. Significance and Use4.1 This test method applies to one-dimensional, laminarflow of water within laboratory-compacted, porous materialssuch as soil.4.2 The hydraulic conductivity of porous materials gener-ally decreases with an increasing amount o
13、f air in the pores ofthe material. This test method applies to porous materialscontaining little or no air. The test method is designed tominimize the amount of air in the test specimen. However, this1This test method is under the jurisdiction ofASTM Committee D18 on Soil andRock and is the direct r
14、esponsibility of Subcommittee D18.04 on HydrologicProperties and Hydraulic Barriers.Current edition approved May 1, 2007. Published July 2007. Originally approvedin 1995. Last previous edition approved in 2002 as D 585695(2002)e1.2For referenced ASTM standards, visit the ASTM website, www.astm.org,
15、orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Olson, R. E., and Daniel, D. E., “Measurement of the Hydraulic Conductivityof Fine-Grained Soils,” Symposium on Permeability and G
16、roundwater ContaminantTransport, ASTM STP 746, ASTM, 1981, pp. 1864.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.test method does not ensure complete saturation of the testspecimen with water. In cases where it is essential to sat
17、uratethe test specimen fully with water, the compacted specimenmay be tested using Test Method D 5084.4.3 This test method applies to permeation of porous mate-rials with water. Permeation with other liquids, such aschemical wastes, can be accomplished using procedures simi-lar to those described in
18、 this test method. However, this testmethod is only intended to be used when water is the permeantliquid.4.4 It is assumed that Darcys law is valid and that thehydraulic conductivity is essentially unaffected by hydraulicgradient. The validity of Darcys law may be evaluated bymeasuring the hydraulic
19、 conductivity of the specimen at threehydraulic gradients; if all measured values are similar (within25 %), then Darcys law may be taken as valid. However, whenthe hydraulic gradient acting on a test specimen is changed, thestate of stress will also change, and, if the specimen or porefluid is compr
20、essible, the volume of the test specimen or porefluid will change. Thus, some change in hydraulic conductivitymay occur when the hydraulic gradient is altered, even in caseswhere Darcys law is valid.4.5 One potential problem with this method of testing is thepossibility that water will flow along th
21、e interface between thetest specimen and the compaction/permeameter ring. Theproblem tends to be of minimal significance for materials thatswell when exposed to water (for example, compacted, clayeysoils) but can be a very serious problem for materials thatmight tend to shrink and pull away from the
22、 walls of thepermeameter. Test Method D 5084 is recommended for anymaterial that tends to shrink when exposed to the permeantliquid.4.6 The correlation between results obtained with this testmethod and the hydraulic conductivities of in-place, com-pacted materials has not been fully investigated. Ex
23、periencehas sometimes shown that flow patterns in small, laboratory-prepared test specimens do not necessarily follow the samepatterns on large field scales and that hydraulic conductivitiesmeasured on small test specimens are not necessarily the sameas larger-scale values. Therefore, the results sh
24、ould be appliedto field situations with caution and by qualified personnel.5. Apparatus5.1 Hydraulic SystemConstant head (Test Method A),falling head (Test Methods B, C, and D), or constant rate offlow (Test Method E) systems may be used provided they meetthe criteria outlined as follows:5.1.1 Const
25、ant HeadThe system must be capable ofmaintaining a constant hydraulic pressure or head to within 65 % and shall include means to measure hydraulic pressures orheads to within the prescribed tolerance. In addition, the headloss across the test specimen must be held constant to within 65 % and shall b
26、e measured with the same accuracy or better.Pressures shall be measured by a pressure gage, electronicpressure transducer, or any other device of suitable accuracy.Head of liquid in a standpipe may be measured with agraduated pipette, ruler, scale, or other device of suitableaccuracy.5.1.2 Falling H
27、eadThe system shall allow for measure-ment of the applied head loss, thus hydraulic gradient, towithin6 5 % or better at any time. In addition, the ratio ofinitial head loss divided by final head loss over an interval oftime shall be measured such that this computed ratio is accurateto within 6 5 %.
28、 The head loss shall be measured with apressure gage, electronic pressure transducer, engineers scale,graduated pipette, or any other device of suitable accuracy.Falling head tests may be performed with either a constanttailwater elevation (Test Method B), rising tailwater elevation(Test Method C),
29、or increasing tailwater elevation (TestMethod D).5.1.3 Constant Rate of FlowThe system must be capableof maintaining a constant rate of flow through the specimen towithin 6 5 % or better. Flow measurement or control shall beby calibrated syringe, graduated pipette, or other device ofsuitable accurac
30、y. The head loss across the specimen shall bemeasured to an accuracy of 6 5 % or better using an electronicpressure transducer or other device of suitable accuracy. Ameans to ensure that the head being measured is not affected bysidewall leakage should be included. More information ontesting with a
31、constant rate of flow is given in the literature4.5.2 Flow Measurement SystemBoth inflow and outflowvolumes shall be measured or controlled. Flow volumes shallbe measured by a graduated accumulator, graduated pipette,graduated cylinder, vertical standpipe in conjunction with anelectronic pressure tr
32、ansducer, marriotte bottle, or othervolume-measuring device of suitable accuracy. For long-termtests, evaporative losses may be significant and should beaccounted for using a suitable correction procedure.5.2.1 Flow AccuracyRequired accuracy for the quantityof flow measured over an interval of time
33、is 6 5 % or better.5.2.2 Head LossesHead losses in the tubes, valves, po-rous end pieces, and filter paper may lead to error. To guardagainst such errors, the permeameter shall be assembled withno specimen inside (but with any porous end pieces or sheetsof filter paper that will be used) and then th
34、e hydraulic systemfilled. If a constant or falling head test is to be used, thehydraulic pressures or heads that will be used in testing aspecimen shall be applied, and the rate of flow measured withan accuracy of 6 5 % or better. This rate of flow shall be atleast ten times greater than the rate of
35、 flow that is measuredwhen a specimen has been compacted inside the permeameterand the same hydraulic pressures or heads are applied. If aconstant rate of flow test is to be used, the rate of flow to beused in testing a specimen shall be supplied to the permeameterand the head loss measured. The hea
36、d loss without a specimenshall be less than 0.1 times the head loss when a specimen ispresent.5.3 Permeameter CellThe permeameter cell shall consistof a rigid-wall compaction mold into which the material to betested is compacted and in which the compacted material ispermeated; and two end plates to
37、control flow into and out ofthe test specimen.Aswell ring may be provided as discussed in4Olsen, H. W., Gill, J. D., Willden, A. T., and Nelson, N. R.,“ Innovations inHydraulic Conductivity Measurements,” Transportation Research Record No. 1309,Transportation Research Board, National Research Counci
38、l, Washington, DC, 1991.D 5856 95 (2007)25.3.2. The permeameter shall be designed and operated so thatpermeant water flows downward through the test specimen,although upward flow may be used if the top of the specimenis protected from upward movement by a rigid porous element.5.3.1 Compaction Mold/P
39、ermeameter RingThe compac-tion mold/permeameter ring shall be constructed of a rigidmaterial that will not be damaged during compaction of the testspecimen and that will not undergo adverse chemical reactionswith the test material or permeant water. Materials such assteel, aluminum, brass, plastic,
40、and glass have been used. Themold shall be sufficiently rigid so that its expansion when thepermeameter is pressurized is negligibly small. The mold canbe any cylindrical shape so long as: the cross-sectional areaalong the direction of flow does not vary by more than 6 2%;height and diameter are eac
41、h $ 25 mm; height does not varyby more than 6 1 %, and the largest particle and clod size inthe compacted specimen is #16 the lesser of the height ordiameter.5.3.2 Swell RingThe top of the permeameter may bedesigned to function in one of three ways: (1) to allow norestraint against swelling (see Fig
42、. 1), in which case a swellring separates the compaction mold/permeameter ring from thetop plate; (2) to allow no swelling of the test specimen (see Fig.2), in which case no swell ring is provided; or (3) to control thevertical stress that is applied to the test specimen (see Fig. 3),in which case a
43、 swell ring may or may not be needed,depending upon how the top plate is designed and how thevertical stress is applied. If a swell ring is used, it shall beconstructed of a rigid material that will not react adversely withthe test material or permeant water, shall have the samediameter or width as
44、the compaction mold/permeameter ring,and shall be sufficiently high to allow free swelling of the testspecimen or to accommodate stress-control apparatus. Sandmay be placed in the swell ring to minimize erosion of thespecimen from influent flow provided that the sand is includedin the measurement of
45、 head losses in the permeameter (see5.2.2).5.3.3 Stress-Control ApparatusIf the upper surface of thecompacted test specimen is subjected to a controlled verticalstress, the stress shall be applied through a rigid plate using anymeans that maintains the stress within 6 5 % of the desiredvalue.5.3.4 B
46、ottom PlateThe bottom plate shall be constructedof rigid material that does not react adversely with the testmaterial or permeant liquid. The plate shall serve the purposeof preventing the test specimen from swelling downward,supporting the test specimen, collecting effluent liquid from thebase of t
47、he test specimen, and ensuring one-dimensional flownear the effluent end of the test specimen. The base plate shallbe sealed to the compaction mold/permeameter ring, forFIG. 1 Compaction-Mold Permeameter with No Restraint AgainstSwelling at Top of Test SpecimenFIG. 2 Compaction-Mold Permeameter in W
48、hich Test SpecimenCannot SwellFIG. 3 Compaction-Mold Permeameter With a Controlled VerticalStress Applied to the Top of the Test SpecimenD 5856 95 (2007)3example, with an O-ring, to prevent leakage. Checks for leaks,conducted without soil in the cell, are helpful to ensureadequacy of the seals. Care
49、ful examination of the seal isparticularly important when the apparatus is disassembled andre-assembled during the test. The bottom plate shall contain aporous material (such as porous plastic, porous metal, porouscorundum, or well-compacted sand) that is far more permeablethan the test specimen (5.2.2 ensures that this is the case) andthat has the same overall diameter or width as the testspecimen. Two base plate designs are acceptable:5.3.4.1 Single-RingThis design (Fig. 1, Fig. 2, and Fig. 3)consists of a single porous material with the same diamet
