1、Designation:D549306(Reapproved 2011)Standard Test Method forPermittivity of Geotextiles Under Load1This standard is issued under the fixed designation D5493;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A
2、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 the determination of the waterpermittivity behavior of geotextiles in a direction normal to theplane of the geotext
3、ile when subjected to specific normalcompressive loads.1.2 Use of this test method is limited to geotextiles.This testmethod is not intended for application with geotextile-relatedproducts such as geogrids,geonets,geomembranes,and othergeocomposites.1.3 The values stated in SI units are to be regard
4、ed as thestandard.The inch-pound units given in parentheses are forinformation only.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 safety and health practices and de
5、termine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D123 Terminology Relating to TextilesD653 Terminology Relating to Soil,Rock,and ContainedFluidsD4354 Practice for Sampling of Geosynthetics and RolledErosion Control Products(RECPs)for Testing
6、D4439 Terminology for GeosyntheticsD4491 Test Methods for Water Permeability of Geotextilesby PermittivityD4716 Test Method for Determining the(In-plane)FlowRate per Unit Width and Hydraulic Transmissivity of aGeosynthetic Using a Constant HeadE11 Specification for Woven Wire Test Sieve Cloth and Te
7、stSieves3.Terminology3.1 Definitions:3.1.1 geotextile,nany permeable textile material usedwith foundation,soil,rock,earth,or any other geotechnicalengineering related material as an integral part of a manmadeproject,structure,or system(see Terminology D4439).3.1.2 hydraulic gradient,i,nthe loss of h
8、ydraulic head perunit distance of flow,dh/dL(see Test Method D4716).3.1.3 permittivity,(),(T-1),nof geotextiles,the volumet-ric flow rate of water per unit cross-sectional area per unit headunder laminar flow conditions,in the normal direction througha geotextile(see Terminology D4439).3.2 For the d
9、efinitions of other terms relating to geotextiles,refer to Terminology D4439.For the definitions of textileterms,refer to Terminology D123.For the definitions ofcoefficient of permeability,refer to Terminology D653.4.Summary of Test Method4.1 This test method provides a procedure for measuring thewa
10、ter flow,in the normal direction through a known crosssection of a single layer of a geotextile at predeterminedconstant hydraulic heads over a range of applied normalcompressive stresses.4.2 The permittivity of a geotextile,can be determined bymeasuring the flow rate of water,in the normal directio
11、n,through a known cross section of a geotextile at predeterminedconstant water heads.4.3 Water flow through geotextiles can be laminar,transient,or turbulent,and therefore permittivity cannot be taken as aconstant.5.Significance and Use5.1 The thickness of a geotextile decreases with increase inthe
12、normal compressive stress.This decrease in thickness mayresult in the partial closing or the opening of the voids ofgeotextile depending on its initial structure and the boundaryconditions.5.2 This test method measures the permittivity due to achange of void structure of a geotextile as a result of
13、an appliedcompressive stress.1This test method is under the jurisdiction of ASTM Committee D35 onGeosynthetics and is the direct responsibility of Subcommittee D35.03 on Perme-ability and Filtration.Current edition approved June 1,2011.Published July 2011.Originally approvedin 1993.Last previous edi
14、tion approved in 2006 as D5493 06.DOI:10.1520/D5493-06R11.2For 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.Copyrigh
15、t ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 6.Apparatus6.1 The apparatus is a constant head permeameter.Generalguidance on the hydraulic design of a constant head permeame-ter can be found in Test Method D4491.6.2 The components installed aro
16、und the test specimen aredesigned in such a way that a normal load can be applieduniformly on the entire flow surface without restraining sig-nificantly the flow rate.The permittivity of the apparatus,calculated using the calibration curve established in section 10,shall be at least 10 times greater than the permittivity of the testspecimen under the hydraulic conditions prevailing during agiven test.However,the central deflection of the loadingmechanism on the plane of the geotextile shall not
