1、Designation:D639106 Designation: D6391 11Standard Test Method forField Measurement of Hydraulic Conductivity Limits ofPorous Materials Using Two Stages of Infiltration from aBoreholeField Measurement of Hydraulic Conductivity UsingBorehole Infiltration1This standard is issued under the fixed designa
2、tion D6391; the number immediately following the designation indicates the year oforiginal 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
3、reapproval.1. Scope1.1This test method covers field measurement of limiting values for vertical and horizontal hydraulic conductivities (alsoreferred to as coeffcients of permeability) of porous materials using the two-stage, cased borehole technique. These limitinghydraulic conductivity values are
4、the maximum possible for the vertical direction and minimum possible for the horizontaldirection. Determination of actual hydraulic conductivity values requires further analysis by qualified personnel.1.2This test method may be utilized for compacted fills or natural deposits, above or below the wat
5、er table, that have a meanhydraulic conductivity less than or equal to 13101.1 This test method covers field measurement of hydraulic conductivity (also referred to as coeffcient of permeability)ofporous materials using a cased borehole technique. When isotropic conditions can be assumed and a flush
6、 borehole is employed,the method yields the hydraulic conductivity of the porous material. When isotropic conditions cannot be assumed, the methodyields limiting values of the hydraulic conductivity in the vertical direction (upper limit) if a single stage is conducted and thehorizontal direction (l
7、ower limit) if a second stage is conducted. For anisotropic conditions, determination of the actual hydraulicconductivity requires further analysis by qualified personnel.1.2 This test method may be used for compacted fills or natural deposits, above or below the water table, that have a meanhydraul
8、ic conductivity less than or equal to 13105m/s (13103cm/s).1.3 Hydraulic conductivity greater than 13105m/s may be determined by ordinary borehole tests, for example, U.S. Bureauof Reclamation 7310 (1)2; however, the resulting value is an apparent conductivity.1.4 For this test method, a distinction
9、 must be made between “saturated” (Ks) and “field-saturated” (Kfs) hydraulic conductivity.True saturated conditions seldom occur in the vadose zone except where impermeable layers result in the presence of perched watertables. During infiltration events or in the event of a leak from a lined pond, a
10、 “field-saturated” condition develops. True saturationdoes not occur due to entrapped air (2). The entrapped air prevents water from moving in air-filled pores that, in turn,pores, whichmay reduce the hydraulic conductivity measured in the field by as much as a factor of two compared with conditions
11、 when trappedair is not present (3). This test method simulatesdevelops the “field-saturated” condition.1.5 Experience with this test method has been predominantly in materials having a degree of saturation of 70 % or more, andwhere the stratification or plane of compaction is relatively horizontal.
12、 Its use in other situations should be consideredexperimental.1.6 As in the case of all tests for hydraulic conductivity, the results of this test pertain only to the volume of soil permeated.Extending the results to the surrounding area requires both multiple tests and the judgment of qualified per
13、sonnel. The number oftests required depends on among other things: the size of the area, the uniformity of the material in that area, and the variation indata from multiple tests.1.7 The values stated in SI units are to be regarded as the standard unless other units specifically are given. By tradit
14、ion in U.S.practice, hydraulic conductivity is reported in cm/s although the common SI units for hydraulic conductivity are m/s.1.8 All observed and calculated values shall conform to the guide for significant digits and rounding established in PracticeD6026.1.8.1 The procedures in this standard tha
15、t are used to specify how data are collected, recorded, and calculated are regarded asthe industry standard. In addition, they are representative of the significant digits that should generally be retained. The procedures1This test method is under the jurisdiction of ASTM Committee D18 on Soil and R
16、ock and is the direct responsibility of Subcommittee D18.04 on Hydrologic Propertiesand Hydraulic Barriers.Current edition approved Feb.Nov. 1, 2006.2011. Published March 2006.January 2012. Originally approved in 1999. Last previous edition approved in 20042006 asD6391-99(2004).D639106. DOI: 10.1520
17、/D6391-06.10.1520/D6391-11.2The boldface numbers in parentheses refer to the list of references at the end of this standard.1This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becaus
18、eit 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 document.Copyright ASTM International, 100 Bar
19、r Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.do not consider material variation, purpose for obtaining the data, special purpose studies, or any considerations for the objectivesof the user. Increasing or reducing the significant digits of reported data to be commensu
20、rate with these considerations is commonpractice. Consideration of the significant digits to be used in analysis methods for engineering design is beyond the scope of thisstandard.1.9 This standard does not purport to address the safety concerns, if any, associated with its use. It is the responsibi
21、lity of theuser of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitationsprior to use. This test method does not purport to address environmental protection problems, as well.2. Referenced Documents2.1 ASTM Standards:3D653 Termino
22、logy Relating to Soil, Rock, and Contained FluidsD1452 Practice for Soil Exploration and Sampling by Auger Borings D1587D1587 Practice for Thin-Walled Tube Sampling of Soils for Geotechnical Purposes D2937D2937 Test Method for Density of Soil in Place by the Drive-Cylinder MethodD3740 Practice for M
23、inimum Requirements for Agencies Engaged in Testing and/or Inspection of Soil and Rock as Used inEngineering Design and Construction D5084D5084 Test Methods for Measurement of Hydraulic Conductivity of Saturated Porous Materials Using a Flexible WallPermeameterD5092 Practice for Design and Installat
24、ion of Ground Water Monitoring WellsD6026 Practice for Using Significant Digits in Geotechnical Data3. Terminology3.1 DefinitionsFor definitions of terms used in this test method, see Terminology :3.1.1 For common definitions of technical terms in this standard, refer to Terminology D653.3.2 Definit
25、ions of Terms Specific to This Standard:3.2.1 horizontal conductivity, kh, nthe hydraulic conductivity in (approximately) the horizontal direction.3.2.2 hydraulic conductivity, (coeffcient of permeability) k, nthe rate of discharge of water under laminar flow conditionsthrough a unit cross-sectional
26、 area of a porous medium under a unit hydraulic gradient and standard temperature conditions (20C).3.2.2.1 DiscussionThe term coeffcient of permeability often is used instead of hydraulic conductivity, but hydraulicconductivity is used exclusively in this test method. A more complete discussion of t
27、he terminology associated with Darcys lawis given in the literature (4). It should be noted that both natural soils and recompacted soils usually are not isotropic with respectto hydraulic conductivity. Except for unusual materials, kh kv.3.2.3 limiting horizontal conductivity, K2, nthe hydraulic co
28、nductivity as determined in Stage 2 of this test method, assumingthe tested medium to be isotropic. For ordinary soils, both compacted and natural, this is the minimum possible value for kh.3.2.4 limiting vertical conductivity, K1, nthe hydraulic conductivity as determined in Stage 1 of this test me
29、thod, assumingthe tested medium to be isotropic. For ordinary soils, both compacted and natural, this is the maximum possible value for kv.3.2.5 test diameter, nthe inside diameter (ID) of the casing.3.2.6 vertical conductivity, kv, nthe hydraulic conductivity in (approximately) the vertical directi
30、on.4. Summary of Test Method4.1The rate of flow of water into soil through the bottom of a sealed, cased borehole is measured in each of two stages, normallywith a standpipe in the falling-head procedure. The standpipe can be refilled as necessary.4.2In Stage 1, the bottom of the borehole is flush w
31、ith the bottom of the casing for maximum effect of kv. The test is continueduntil the flow rate becomes quasi-steady.4.3For Stage 2, the borehole is extended below the bottom of the casing for maximum effect of kh. This stage of the test alsois continued until the flow rate becomes quasi-steady.4.4T
32、he direct results of the test are the limiting hydraulic conductivities4.1 The rate of flow of water into soil through the bottom of a sealed and cased borehole is measured in one or two stages,normally with a standpipe using a falling-head or constant-head procedure. The standpipe is refilled as ne
33、cessary. A schematic ofthe test apparatus is shown in Fig. 1 with the dimensions to be recorded.4.2 Method AMethod A is used when the soil being tested is treated as anisotropic. A falling-head test is conducted in twostages with the bottom of the borehole flush with the bottom of the casing in Stag
34、e 1 and extended below the bottom of the casingas a right circular cylinder in Stage 2 (Fig. 1). The borehole is extended for Stage 2 after Stage 1 is completed.Alimiting hydraulicconductivity is computed from the falling head data in both stages. These limiting hydraulic conductivities are K1 and K
35、2. Theactual hydraulic conductivities , respectively.3For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.D6391
36、112FIG. 1 Schematic of Borehole Test Showing Borehole Flush with Base (Methods B and C, Stage 1 of Method A) and with Extension forStage 2 of Method AD6391 113Stages 1 and 2 are continued until the limiting conductivity for each stage is relatively constant.Methods to calculate actual vertical and h
37、orizontal hydraulic conductivities (kvand khcan be calculated from these values )fromK1 and K2 are described in (5) and (6).4.3 Method BMethod B employs a falling head and is used when the soil being tested is treated as isotropic. A falling headtest is conducted in a borehole flush with the bottom
38、of the casing (Fig. 1). Hydraulic conductivity of the soil is computed fromthe falling head data. The test is continued until the hydraulic conductivity becomes essentially constant.4.4 Method CMethod C employs a Mariotte tube to apply a constant head and is also used when the soil being tested is t
39、reatedas isotropic. A constant head test is conducted in a borehole flush with the bottom of the casing. Hydraulic conductivity of the soilis computed from the steady flow rate measured during the test. The same apparatus and test set up is used for Methods B andC, except the falling-head standpipe
40、used in Method B (Fig. 2a) is replaced by a constant-head Mariotte tube (Fig. 2b).5. Significance and Use5.1 This test method provides a means to measure both the hydraulic conductivity of isotropic materials and the maximumvertical and minimum horizontal hydraulic conductivities of anisotropic mate
41、rials, especially in the low ranges associated withfine-grained clayey soils, 13107m/s to 131011m/s.5.2 This test method particularly is useful for measuring liquid flow through soil moisturehydraulic barriers, such as compactedclay liners or covers barriers used at waste disposalcontainment facilit
42、ies, for canal and reservoir liners, for seepage blankets, andfor amended soil liners, such as those used for retention ponds or storage tanks. Due to the boundary condition assumptions usedin deriving the equations for the limiting hydraulic conductivities, the thickness of the unit tested must be
43、at least six times thetest diameter. 600 mm. This requirement must be is increased to eight test diameters 800 mm if the barrier is not material beingtested is underlain by a drainage blanket or by a material material that is far less permeable than the barrier being tested. permeable.5.3 The soil l
44、ayer being tested must have sufficient cohesion to stand open during excavation of the borehole.5.4 This test method provides a means to measure infiltration rate into a moderately large volume of soil. Tests on large volumesof soil can be more representative than tests on small volumes of soil. Mul
45、tiple installations properly spaced provide a greatervolume and an indication of spatial variability.5.5 The data obtained from this test method are most useful when the soil layer being tested has a uniform distribution ofhydraulic conductivity and of pore space and when the upper and lower boundar
46、y conditions of the soil layer are well defined.5.6 Changes in water temperature can introduce significant errors in the flow measurements. Temperature changes causefluctuations in the standpipe levels, whichwater levels that are not related to flow. This problem is most pronounced when a smalldiame
47、ter standpipe or Marriotte bottle is used in soils having hydraulic conductivities of 531010m/s or less.5.7The effects of temperature changes are taken into account by the use of a dummy installation, the temperature effect gage(TEG). The base of the TEG must be sealed to prevent flow. The fluctuati
48、ons of the TEG are due solely to ambient changes andare used to correct the readings at the flowing tests.5.8If the soil being tested will later be subjected to increased overburden stress, then the hydraulic conductivities can be expectedto decrease as the overburden stress increases. Laboratory hy
49、draulic conductivity tests or these tests under varying surface loadsare recommended for studies of the influence of level of stress on the hydraulic properties of the soil.5.7 The effects of temperature changes and other environmental perturbations are taken into account using a temperature effectgauge (TEG), which is an identical installation with a watertight seal at the bottom of the casing.5.8 If the soil being tested will later be subjected to increased overburden stress, then the hydraulic conductivities can beexpected to decrease as the overburden st
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