1、Designation: D4511 11Standard Test Method forHydraulic Conductivity of Essentially Saturated Peat1This standard is issued under the fixed designation D4511; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision.
2、 A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () 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 saturated,intact cylindrical
3、 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.1.2 Hydraulic conductiv
4、ity 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 UnitsThe values stated in SI units are t
5、o be regardedas the standard. The inch-pound units given in parentheses aremathematical conversions, which are provided for informationpurposes only and are not considered standard.1.3.1 The converted inch-pound units use the gravitationalsystem of units. In this system, the pound (lbf) represents a
6、 unitof force (weight), while the unit for mass is slugs. Theconverted slug unit is not given, unless dynamic (F = ma)calculations are involved.1.4 All observed and calculated values shall conform to theguide for significant digits and rounding established in PracticeD6026.1.4.1 The procedures used
7、to specify how data are collected/recorded and calculated in this standard are regarded as theindustry 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, sp
8、ecial purpose studies, or any consider-ations for the users objectives, and it is common practice 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 en
9、gineering design.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 regulatory limitations prior to us
10、e.2. Referenced Documents2.1 ASTM Standards:3D653 Terminology Relating to Soil, Rock, and ContainedFluidsD1587 Practice for Thin-Walled Tube Sampling of Soils forGeotechnical PurposesD2434 Test Method for Permeability of Granular Soils(Constant Head)D2974 Test Methods for Moisture,Ash, and Organic M
11、atterof Peat and Other Organic SoilsD3740 Practice for Minimum Requirements for AgenciesEngaged in Testing and/or Inspection of Soil and Rock asUsed in Engineering Design and ConstructionD4220 Practices for Preserving and Transporting SoilSamplesD4753 Guide for Evaluating, Selecting, and SpecifyingB
12、alances and Standard Masses for Use in Soil, Rock, andConstruction Materials TestingD6026 Practice for Using Significant Digits in GeotechnicalData2.2 NRC Document:Peat Testing Manual43. Terminology3.1 DefinitionsFor common definitions of terms in thisstandard, refer to Terminology D653.3.2 Definiti
13、ons of Terms Specific to This Standard:3.2.1 deaerated (de-aired) waterwater in 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.1This test me
14、thod is under the jurisdiction ofASTM Committee D18 on Soil andRock and is the direct responsibility of Subcommittee D18.04 on HydrologicProperties and Hydraulic Barriers.Current edition approved Nov. 1, 2011. Published January 2012. Originallyapproved in 1992. Last previous edition approved in 2006
15、 as D451100(2006). DOI:10.1520/D4511-11.2For further information, see “Methods for Measurement of Saturated HydraulicConductivity,” Peat Testing Manual, Technical Memorandum No. 125, NRCCanada, pp. 8084.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Ser
16、vice 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, Publications Section, Building R88,Ottawa, Canada K1A 0R6. Out of print.1*A Summary of Changes section appears at the en
17、d of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.2.3 soakingplacement of a specimen in water for thepurpose of removing gas contained in the pore space, throughbouyancy, and replacement with water to cause saturati
18、on ofthe specimen. This method of saturation does not effectivelyremove all the gas contained in the specimen and 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 testmet
19、hod may be useful in making rough preliminary estimatesof the initial rates of drainage and compression of peat depositswhen 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 underg
20、odramatic volume changes that influence (decrease) the hydrau-lic conductivity of the deposit by several orders of 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 leve
21、ls. Therefore,this test method is not suitable for applications involving gradeincreases, such as embankment construction or placement ofaccess berms alongside drainage ditches.4.3 Undisturbed specimens from apparently homogeneouspeat deposits at the same location often exhibit significantlydifferen
22、t hydraulic conductivity properties due to variations inmaterial composition and sampling procedure.NOTE 1The quality 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 thec
23、riteria of Practice D3740 are generally considered capable of competentand objective testing/sampling/inspection/etc. Users of this standard arecautioned that compliance with Practice D3740 does not in itself ensurereliable results. Reliable results depend on many factors; Practice D3740provides a m
24、eans of evaluating some of those factors.5. Interferences5.1 Due to the generally fibrous texture and extremely highcompressibility of peat, present sampling technologies may notbe able to obtain samples truly representative of the in situconditions. Disturbance caused by sampling and specimenprepar
25、ation as well as heterogeneity existing in situ may causethe hydraulic conductivity determined using this method 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 l
26、istedin 6.1.1 and 6.1.2. The assumption is made that these condi-tions are satisfied if the flow rate, with time, 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
27、 suspected or visuallyverified, notice thereof should be made in the test report.6. Fundamental Test Conditions6.1 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 a
28、test,6.1.2 Flow with the void space saturated with water and noair bubbles in the voids,6.1.3 Flow in the steady 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
29、types of flow involving partial saturation ofvoid space, turbulent flow, and unsteady state of flow aretransient in character and yield variable and time-dependentvalues of hydraulic conductivity; therefore, they require specialtest conditions and procedures.7. Apparatus7.1 Flow DeviceThe flow devic
30、e shall be as shown in Fig.1, fitted with the following components:7.1.1 Constant-Head Filter Tank, as shown in Fig. 1 of TestMethod D2434, 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, s
31、upplied from aself-siphoning burette with attached inverted flask (minimum 750-mLcapacity), filled with deaerated 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 approxima
32、tely 150 cm (6 in.) high.7.1.3 Wire-Screen Support, fabricated from a ring clamp,with an inside diameter greater 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 t
33、hespecimen.7.1.5 Funnel, with a head diameter at least 10 % larger thanthat of the specimen cylinder.7.1.6 Two 400-mL Beakers.7.2 BalanceAbalance or scale conforming to the require-ments of Specification D4753, readable (with no estimate) to0.1 % of the test mass, or better.7.3 Miscellaneous Apparat
34、us and Materials, such as ther-mometers, timer reading to nearest second, soaking pan, pipecutters, trimming 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
35、-to-diameter ratio shall be between 1 and2.8.2 Prepare specimens from tube samples secured in accor-dance with Practice D1587, or other acceptable undisturbedsampling procedure, yielding cylindrical samples obtained intight-fitting, rigid-metal core holders (Note 3). Preserve andtransport the specim
36、ens in accordance with the practice forGroup D samples in Practices D4220 (Note 4).NOTE 3Samples of fibrous 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.55Such a device, the P
37、eat Core Cutter, is described fully in Peat Testing Manual,Technical Memorandum No. 125, NRC Canada, Section 1.1.2, pp. 710.D4511 112NOTE 4The integrity of a sample contained in a sampler liner or coreholder is best preserved if the sample ends are trimmed flush with the endsof the liner and capped
38、using tight-fitting, rigid-metal end caps, securelytaped in place and dipped in micro-crystalline wax.8.3 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,
39、 secure the sample container firmly, withoutdeformation, in a vertical position and cut off a suitable 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
40、a piece of cheesecloth and secure the cheese-cloth to the cylinder with a rubber band.NOTE 5A chain-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
41、 covering theend of the specimen should rest on screening that is permeableenough to permit free flow 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 fl
42、ow of water onto thetop of the specimen cylinder. Soak the specimen for 72 h.NOTE 6Water used for soaking 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 l
43、aboratory, to remove suspended solids. The type of water usedshould be noted in the report under remarks (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 effect
44、s of different types of water on thehydraulic conductivity of peat.NOTE 7Continuing slow decomposition 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
45、pre-wetted wire screensupport, and wipe excess water off the specimen cylinder.8.6 Place the upper 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
46、 of 425-m (No.40) wire mesh screening in water, and place it on the topsurface of the specimen.8.7 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 main
47、tain the desired constant head. Tominimize compression of the peat, limit the head of waterabove the 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 con
48、venient time to start the flow rate measure-ment. At the appointed time, replace the beaker with a 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 t
49、hat water is not spilled or lost.9.1.1 Determine the volume of flow in the first time intervalas the 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).FIG. 1 Diagram for the Constant-Head System for Conductivity MeasurementD4511 113NOTE 8Graduated cylinders may be used in lieu of beakers as long asthe accuracy of the flow rate determination is not impaired.9.1.2 Repeat the flow measurements and prepare a plot ofcumulative flow quantity at the respective ti
