1、Designation: D 4511 00 (Reapproved 2006)Standard Test Method forHydraulic Conductivity of Essentially Saturated Peat1This standard is issued under the fixed designation D 4511; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the ye
2、ar 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. Scope*1.1 This test method covers the determination of the hy-draulic conductivity (permeability) of essentially saturat
3、ed,intact cylindrical specimens of peat when the hydraulic con-ductivity is greater than 1 3 107m/s (1 3 105cm/s). Duringthe test, the specimens are contained in the core holder, or inright, regular cylindrical sections cut from the sampling tube inwhich they were originally obtained in the field.1.
4、2 Hydraulic conductivity is calculated on the basis of themeasured constant flow rate through the specimen underconstant head.2For verification, flow rate determinations maybe made at two or more values of constant head withcorresponding calculations of hydraulic conductivity.1.3 The values stated i
5、n SI units are to be regarded as thestandard.1.4 All observed and calculated values shall conform to theguide for significant digits and rounding established in PracticeD 6026.1.4.1 The procedures used to specify how data are collected/recorded and calculated in this standard are regarded as theindu
6、stry standard. In addition, they are representative of thesignificant digits that should generally be retained. The proce-dures used do not consider material variation, purpose forobtaining the data, special purpose studies, or any consider-ations for the users objectives, and it is common practice
7、toincrease or reduce significant digits of reported data to becommensurate with these considerations. It is beyond the scopeof this standard to consider significant digits used in analysismethods for engineering design.1.5 This standard does not purport to address all of thesafety concerns, if any,
8、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 ASTM Standards:3D 653 Terminology Relating to Soil, Rock, and Contain
9、edFluidsD 1587 Practice for Thin-Walled Tube Sampling of Soilsfor Geotechnical PurposesD 2434 Test Method for Permeability of Granular Soils(Constant Head)D 2974 Test Methods for Moisture, Ash, and Organic Mat-ter of Peat and Other Organic SoilsD 3740 Practice for Minimum Requirements for AgenciesEn
10、gaged in the Testing and/or Inspection of Soil and Rockas Used in Engineering Design and ConstructionD 4220 Practices for Preserving and Transporting SoilSamplesD 4753 Guide for Evaluating, Selecting, and SpecifyingBalances and Standard Masses for Use in Soil, Rock, andConstruction Materials Testing
11、D 6026 Practice for Using Significant Digits in Geotechni-cal Data2.2 NRC Document:Peat Testing Manual43. Terminology3.1 DefinitionsFor common definitions of terms in thisstandard, refer to Terminology D 653.3.2 Definitions of Terms Specific to This Standard:3.2.1 deaerated (de-aired) waterwater in
12、which theamount of dissolved gas (air) has been reduced.3.2.2 flow ratethe quantity of water flowing through thetest specimen in a given period of time, when subjected to acertain constant head differential.3.2.3 soakingplacement of a specimen in water for thepurpose of removing gas contained in the
13、 pore space, throughbouyancy, and replacement with water to cause saturation ofthe specimen. This method of saturation does not effectively1This test method is under the jurisdiction ofASTM Committee D18 on Soil andRock and is the direct responsibility of Subcommittee D18.04 on HydrologicProperties
14、of Soil and Rock.Current edition approved Feb. 1, 2006. Published March 2006. Originallyapproved in 1992. Last previous edition approved in 2000 as D 4511 00.2For further information, see “Methods for Measurement of Saturated HydraulicConductivity,” Peat Testing Manual, Technical Memorandum No. 125,
15、 NRCCanada, pp. 8084.3For 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.4National Research Council of Canada, Pu
16、blications Section, Building R88,Ottawa, Canada K1A 0R6. Out of print.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.remove all the gas contained in the specimen and
17、does notprevent the continuous slow formation of gas from decompo-sition under anaerobic conditions.4. Significance and Use4.1 Values of hydraulic conductivity determined by this testmethod may be useful in making rough preliminary estimatesof the initial rates of drainage and compression of peat de
18、positswhen the only effective stress increase on the deposit is thatresulting from a moderate, gradual lowering of the water table.4.2 Even under light, sustained loads, peat will undergodramatic volume changes that influence (decrease) the hydrau-lic conductivity of the deposit by several orders of
19、 magnitude.This test method does not offer provisions for the determina-tion of the relationship between hydraulic conductivity and thevoid ratios corresponding to increasing stress levels. Therefore,this test method is not suitable for applications involving gradeincreases, such as embankment const
20、ruction or placement ofaccess berms alongside drainage ditches.4.3 Undisturbed specimens from apparently homogeneouspeat deposits at the same location often exhibit significantlydifferent hydraulic conductivity properties due to variations inmaterial composition and sampling procedure.NOTE 1The qual
21、ity of the result produced by this standard isdependent on the competence of the personnel performing it, and thesuitability of the equipment and facilities used. Agencies that meet thecriteria of Practice D 3740 are generally considered capable of competentand objective testing/sampling/inspection/
22、etc. Users of this standard arecautioned that compliance with Practice D 3740 does not in itself ensurereliable results. Reliable results depend on many factors; Practice D 3740provides a means of evaluating some of those factors.5. Interferences5.1 Due to the generally fibrous texture and extremely
23、 highcompressibility of peat, present sampling technologies may notbe able to obtain samples truly representative of the in situconditions. Disturbance caused by sampling and specimenpreparation as well as heterogeneity existing in situ may causethe hydraulic conductivity determined using this metho
24、d to besignificantly different than the in situ hydraulic conductivity.5.2 There are no provisions in this test method for verifica-tion of compliance with the fundamental test conditions listedin 6.1.1 and 6.1.2. The assumption is made that these condi-tions are satisfied if the flow rate, with tim
25、e, is a linearrelationship.5.3 The result of the test may be influenced by flow throughopen passages between the specimen and the rigid wall of thespecimen container. If such a condition is suspected or visuallyverified, notice thereof should be made in the test report.6. Fundamental Test Conditions
26、6.1 The following ideal test conditions are prerequisite forlaminar flow of water through porous media under constant-head conditions:6.1.1 Continuity of flow with no volume change during atest,6.1.2 Flow with the void space saturated with water and noair bubbles in the voids,6.1.3 Flow in the stead
27、y state with no changes in hydraulicgradient, and6.1.4 Direct proportionality of flow velocity with hydraulicgradients below certain values, after which flow becomesturbulent.6.2 All other types of flow involving partial saturation ofvoid space, turbulent flow, and unsteady state of flow aretransien
28、t in character and yield variable and time-dependentvalues of hydraulic conductivity; therefore, they require specialtest conditions and procedures.7. Apparatus7.1 Flow DeviceThe flow device shall be as shown in Fig.1, fitted with the following components:7.1.1 Constant-Head Filter Tank, as shown in
29、 Fig. 1 of TestMethod D 2434, to supply water and to remove most of the airfrom the water. The tank shall be fitted with a suitable siphon.NOTE 2Alternatively, deaerated water may be used, supplied from aself-siphoning burette with attached inverted flask (minimum 750-mLcapacity), filled with deaera
30、ted water, and closed with a rubber stopperholding a tube, 150 cm (6 in.) long with the end cut diagonally.7.1.2 Upper Reservoir, of the same diameter as the sam-pling cylinder and approximately 150 cm (6 in.) high.7.1.3 Wire-Screen Support, fabricated from a ring clamp,with an inside diameter great
31、er than the specimen cylinder andcovered with 425-m (No. 40) wire mesh screening.7.1.4 Circular Disk, cut from 425-m (No. 40) wire meshscreening, with a diameter 1 mmm smaller than that of thespecimen.7.1.5 Funnel, with a head diameter at least 10 % larger thanthat of the specimen cylinder.7.1.6 Two
32、 400-mL Beakers.7.2 BalanceAbalance or scale conforming to the require-ments of Specification D 4753, readable (with no estimate) to0.1 % of the test mass, or better.7.3 Miscellaneous Apparatus and Materials, such as ther-mometers, timer reading to nearest second, soaking pan, pipecutters, trimming
33、knife, cheese cloth, rubber bands, vinylelectrical tape, and micro-crystalline wax.8. Specimen Preparation and Set Up8.1 Specimens shall have a minimum diameter of 73 mm(2.87 in.). The height-to-diameter ratio shall be between 1 and2.8.2 Prepare specimens from tube samples secured in accor-dance wit
34、h Practice D 1587, or other acceptable undisturbedsampling procedure, yielding cylindrical samples obtained intight-fitting, rigid-metal core holders (Note 3). Preserve andtransport the specimens in accordance with the practice forGroup D samples in Practices D 4220 (Note 4).NOTE 3Samples of fibrous
35、 peat from shallow depths can be securedwith the least amount of disturbance using a rotary type sampling deviceequipped with a thin cutting edge, serrated with saw-teeth.5NOTE 4The integrity of a sample contained in a sampler liner or coreholder is best preserved if the sample ends are trimmed flus
36、h with the endsof the liner and capped using tight-fitting, rigid-metal end caps, securelytaped in place and dipped in micro-crystalline wax.5Such a device, the Peat Core Cutter, is described fully in Peat Testing Manual,Technical Memorandum No. 125, NRC Canada, Section 1.1.2, pp. 710.D 4511 00 (200
37、6)28.3 The specimen is tested in a section of the originalsample container without extrusion. If the length of the samplecontainer initially is not within the proper range for height-to-diameter ratio, secure the sample container firmly, withoutdeformation, in a vertical position and cut off a suita
38、ble testsection with a pipe cutter (Note 5). Trim the peat specimenflush with the cylinder at both ends. Determine and record themass of the specimen and cylinder. Cover the bottom of thespecimen with a piece of cheesecloth and secure the cheese-cloth to the cylinder with a rubber band.NOTE 5A chain
39、-type pipe cutter, such as those used for cuttingautomotive exhaust system pipe, is recommended.8.4 Place the specimen inside a soaking pan with a depthgreater than the specimen length. The cheesecloth covering theend of the specimen should rest on screening that is permeableenough to permit free fl
40、ow of water to the specimen; separatingthe specimen from the bottom of the pan. Slowly fill the panwith water (Note 6) to a depth approximately 6 mm (0.25 in.)below the top of the specimen.Avoid the flow of water onto thetop of the specimen cylinder. Soak the specimen for 72 h.NOTE 6Water used for s
41、oaking and subsequent permeation may bedeaerated tap water, distilled water, or water obtained from the samplelocation in the field. In the latter case, the water must be filtered, prior touse in the laboratory, to remove suspended solids. The type of water usedshould be noted in the report under re
42、marks (11.2), however; it should berecognized that hydraulic conductivity determined by this method isinfluenced by so many factors, that the results are not suitable forcomparative study of the effects of different types of water on thehydraulic conductivity of peat.NOTE 7Continuing slow decomposit
43、ion of peat is accompanied bythe formation of gases. Total saturation may not be achieved by soakingalone.8.5 Remove the specimen from the soaking pan, remove thecheesecloth, place the specimen on the pre-wetted wire screensupport, and wipe excess water off the specimen cylinder.8.6 Place the upper
44、reservoir on top of the specimencylinder and seal the joint with vinyl electrical tape, a widerubber band, or a coat of micro-crystalline wax, to effect awatertight connection. Dip the cylindrical disk of 425-m (No.40) wire mesh screening in water, and place it on the topsurface of the specimen.8.7
45、Position a funnel and beaker beneath the specimen.Carefully add water (Note 6) to the upper reservoir to activatethe siphoning system discussed in 7.1.1 (shown in principle inFig. 1) and adjust to maintain the desired constant head. Tominimize compression of the peat, limit the head of waterabove th
46、e specimen to 50 to 100 mm.8.8 The ambient temperature during the test should not varyby more than 63C (65.5F).9. Test Procedure9.1 When it appears that a constant flow rate has beenattained, set a convenient time to start the flow rate measure-ment. At the appointed time, replace the beaker with a
47、dry,clean beaker of known tare mass. After some suitable, conve-nient time interval, replace the beaker by a second dry, cleanbeaker of known tare mass, and weigh the first beaker. Exercisegreat care that water is not spilled or lost.9.1.1 Determine the volume of flow in the first time intervalas th
48、e difference between the mass of the beaker and water, andthe tare mass of the beaker (using the assumption that 1 mL ofwater has a mass of 1 g) (Note 8).NOTE 8Graduated cylinders may be used in lieu of beakers as long asthe accuracy of the flow rate determination is not impaired.FIG. 1 Diagram for
49、the Constant-Head System for Conductivity MeasurementD 4511 00 (2006)39.1.2 Repeat the flow measurements and prepare a plot ofcumulative flow quantity at the respective times until aconstant flow rate has been defined by a minimum of fourpoints falling reasonably close to a straight line. A suitableminimum time interval between flow measurements is the timerequired for accumulation of a volume of water, correspondingto at least 10 % of the tare mass of the beaker.9.2 Measure the value of the constant head applied duringthe flow rate determination as the ele
