1、Designation: D7931 17Standard Guide forSpecifying Drainage Geocomposites1This standard is issued under the fixed designation D7931; 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
2、indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This guide presents a guideline specifying a drainagegeocomposite product; it specifically provides recommenda-tions to determine the allowable flow rate of
3、a candidatedrainage geocomposite. The resulting value is then comparedto a required (or design) flow rate for a product-specific andsite-specific factor of safety.1.2 This guide is intended to aid designers, purchasers,installers, contractors, owners, operators, and agencies inestablishing minimum g
4、uidelines for drainage geocompositematerials. This guide is not to be used for manufacturersquality control purposes, nor a construction quality assurancespecification.1.3 This guide does not address the required (or design)flow rate value, nor the subsequent factor of safety values,which are typica
5、lly design specific.1.4 The procedures recommended in this guide use ASTMtest methods.1.5 This guide is applicable to all types of drainage geo-composites regardless of their core configuration or geotextiletype. It can also be used to evaluate thick nonwoven geotextilesthat provide drainage.1.6 The
6、 values stated in either SI units or inch-pound unitsare to be regarded separately as standard. The values stated ineach system may not be exact equivalents; therefore, eachsystem shall be used independently of the other. Combiningvalues from the two systems may result in nonconformancewith the stan
7、dard.1.7 This guide offers an organized collection of informationor a series of options and does not recommend a specific courseof action. This guide cannot replace education or experienceand should be used in conjunction with professional judgment.Not all aspects of this guide may be applicable in
8、all circum-stances. This guide is not intended to represent or replace thestandard of care by which the adequacy of a given professionalservice must be judged, nor should this guide be appliedwithout consideration of a projects many unique aspects. Theword standard in the title of this guide means o
9、nly that theguide has been approved through the ASTM Internationalconsensus process.1.8 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, health, and environment
10、al practices and deter-mine the applicability of regulatory limitations prior to use.1.9 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Gu
11、ides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D1987 Test Method for Biological Clogging of Geotextile orSoil/Geotextile FiltersD2990 Test Methods for Tensile, Compressive, and FlexuralCreep and C
12、reep-Rupture of PlasticsD4354 Practice for Sampling of Geosynthetics and RolledErosion Control Products (RECPs) for TestingD4439 Terminology for GeosyntheticsD4716/D4716M Test Method for Determining the (In-plane)Flow Rate per Unit Width and Hydraulic Transmissivityof a Geosynthetic Using a Constant
13、 HeadD4873/D4873M Guide for Identification, Storage, and Han-dling of Geosynthetic Rolls and SamplesD5321/D5321M Test Method for Determining the ShearStrength of Soil-Geosynthetic and Geosynthetic-Geosynthetic Interfaces by Direct ShearD5322 Practice for Laboratory Immersion Procedures forEvaluating
14、 the Chemical Resistance of Geosynthetics toLiquidsD6243/D6243M Test Method for Determining the Internaland Interface Shear Strength of Geosynthetic Clay Linerby the Direct Shear Method1This guide is under the jurisdiction ofASTM Committee D35 on Geosyntheticsand is the direct responsibility of Subc
15、ommittee D35.03 on Permeability andFiltration.Current edition approved Sept. 1, 2017. Published September 2017. Originallyapproved in 2017. DOI: 10.1520/D7931-17.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book
16、of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognize
17、d principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1D6388 Practice for Tests to Evaluate the Chemical Resis-tance of Geo
18、nets to LiquidsD6389 Practice for Tests to Evaluate the Chemical Resis-tance of Geotextiles to LiquidsD6747 Guide for Selection of Techniques for Electrical LeakLocation of Leaks in GeomembranesD7001 Specification for Geocomposites for Pavement EdgeDrains and Other High-Flow ApplicationsD7273/D7273M
19、 Guide for for Acceptance Testing Require-ments for Geonets and Geonet Drainage GeocompositesD7361 Test Method for Accelerated Compressive Creep ofGeosynthetic Materials Based on Time-Temperature Su-perposition Using the Stepped Isothermal MethodD7406 Test Method for Time-Dependent (Creep) Deforma-t
20、ion Under Constant Pressure for Geosynthetic DrainageProductsD7852 Practice for Use of an Electrically Conductive Geo-textile for Leak Location Surveys3. Terminology3.1 Definitions:3.1.1 For definitions of terms related to geosynthetics, referto Terminology D4439.3.2 Definitions of Terms Specific to
21、 This Standard:3.2.1 agency, nin geosynthetics, the organization thatreviews the permit application for compliance with the agen-cys regulation and all quality assurance documentation beforeand after construction.3.2.2 contractor, nin geosynthetics, the party or organiza-tion that has the responsibi
22、lity for the construction of theman-made project, structure, or system.3.2.3 designer, nin geosynthetics, the person or organiza-tion that designs a man-made project, structure, or system thatfulfills the owner/operators requirements and meets or exceedsthe minimum requirements of the agency.3.2.4 i
23、nstaller, nin geosynthetics, the party that installs, orfacilitates installation of, any materials purchased from manu-facturers or suppliers.3.2.5 operator, nin geosynthetics, the person or organiza-tion that operates the man-made project, structure, or system.3.2.6 owner, nin geosynthetics, the pe
24、rson or organizationthat owns the man-made project, structure, or system.3.2.7 purchaser, nin geosynthetics, the person, company,or organization that purchases any materials or work to beperformed.3.2.8 q100,ninitial flow rate for a drainage geocompositeas determined under simulated conditions for 1
25、00-h duration.3.2.9 qallow,nallowable flow rate for a drainage geocom-posite.4. Significance and Use4.1 This guide is intended to aid designers, purchasers,installers, contractors, owners, operators, and agencies inestablishing the minimum criteria to specify drainage geocom-posites. Specifically, t
26、his guide presents a methodology fordetermining the allowable flow rate of a candidate drainagegeocomposite. The resulting value is then compared to arequired (or design) flow rate for a product-specific andsite-specific factor of safety.4.2 It is recognized that there are other products that mayach
27、ieve the same performance requirements but are not listedin this document. Manufacturers of such products are invited toimplement this standard guide with the appropriate informa-tion.4.3 It should be recognized that parties, organizations, orrepresentatives may perform additional tests other than t
28、hoserequired in this guide. In this case, the more stringent project-specific tests will then take precedence.4.4 By simulating site-specific conditions (inclusive of site-specific liquids and temperatures except for load durationbeyond 100 h, chemical/biological clogging, and geotextileintrusion),
29、additional reduction factors need not be explicitlyaccounted for in certain products.5. Classification5.1 GeneralThis guide covers geocomposite drainageproducts or structures intended for blanket subsurface drainageapplications. Five distinctly different product designs areincluded in this guide as
30、geocomposite drainage products:5.2 Biaxial Geonet GeocompositeA geonet consisting ofan integrally connected parallel set of ribs overlying a similarset of ribs at typically opposite angles, typically heat laminatedwith nonwoven geotextiles on the top and bottom to form thegeocomposite. Note that sin
31、gle-sided biaxial geonet geocom-posites are available in the marketplace as well; in thatparticular case only one side of the geonet will be heatlaminated with a nonwoven geotextile.5.3 Triaxial Geonet GeocompositeA geonet consisting ofan integrally connected parallel set of ribs, or forming aninteg
32、rated web with a flow direction mainly oriented in themachine direction, typically heat laminated with nonwovengeotextiles on the top and bottom to form the geonet geocom-posite. It should be noted that single-sided triaxial geonetgeocomposites are available in the marketplace as well; in thatpartic
33、ular case only one side of the geonet will be heatlaminated with a nonwoven geotextile.5.4 Multilinear Drainage GeocompositeA manufacturedproduct composed of a series of parallel single drainageconduits regularly spaced across its width sandwiched betweentwo or more geosynthetics.5.5 Structured Geom
34、embrane SystemA geomembranewith integrated drainage nubs, spikes, or both. The drainagenubs, when overlain or heat laminated by a filter fabric (heatburnished on one side), will form the structured geomembranedrainage geocomposite.5.6 Sheet Drain GeocompositeA three-dimensional struc-tured core cons
35、isting of integrally connected voids with a flowdirection mainly oriented in the machine direction, typicallyheat laminated with a nonwoven geotextile or monofilamentfilter either on the top or bottom (or both) to form the drainagegeocomposite. It should be noted that single-sided sheet draingeocomp
36、osites are available in the marketplace as well; in thatD7931 172particular case only one side of the structure will be laminatedwith a nonwoven geotextile or monofilament filter geotextile.5.7 Geocomposite Edge DrainA geotextile wrappedaround a structural polymer drainage core used for subsurfacedr
37、ainage applications in highway, turf, and environmentalapplications. The product is typically 1 in. (25 mm) thick andavailable in 6 in. (150 mm), 12 in. (300 mm), 18 in. (450 mm),24 in. (600 mm), 30 in. (750 mm), and 36 in. (900 mm) widths.6. Determination of the qallowof a Candidate DrainageGeocomp
38、osite6.1 Basic Formulation3This guide is focused on determi-nation of a qallowvalue using the following formula:qallow5 q100F1RFCR1RFCC1RFBC1RFGIG(1)where:qallow= allowable flow rate for a drainage geocomposite,q100= initial flow rate determined under simulated condi-tions for 100-h duration,RFCR= r
39、eduction factor for creep to account for long-termbehavior,RFCC= reduction factor for chemical clogging,RFBC= reduction factor for biological clogging, andRFGI= reduction factor for geotextile intrusion past theinitial 100-h seating time.NOTE 1The value of qallowis typically used to determine thepro
40、duct-specific and site-specific flow rate factor of safety as follows:FS 5qallowqreqd(2)The value of qreqdis a design issue and is not addressed in this guide.Likewise, the numeric value of the factor of safety is not addressed inthis guide. Suffice it to say that, depending on the duration and crit
41、ical-ity of the situation, FS values should be conservative unless experienceallows otherwise.6.2 Upon selecting the candidate drainage geocompositeproduct, one must obtain the 100-h duration flow rate accord-ing to the Test Method D4716/D4716M transmissivity test orother appropriate transmissivity
42、test method such as Specifi-cation D7001, which is more appropriate for high-flow appli-cations (see 6.2.2 for more background on which transmissivitytest method to select). This establishes the base value to whichdrainage core creep beyond 100 h, clogging from chemicalsand biological matter, and ge
43、otextile intrusion must be ac-counted for.6.2.1 It is recognized that the default duration listed in TestMethod D4716/D4716M is 15 min. This guide purposelyrequires that the test conditions be maintained for 100 h, andsimulating site-specific loading and boundary conditions.6.2.2 While Test Method D
44、4716/D4716M has historicallybeen the “default” transmissivity test for geosynthetic drainagegeocomposites, this transmissivity test method is limited to thesize of the specimen being tested. Zimmel et al. (2011)identified that specimen size can significantly affect transmis-sivity tests performed in
45、 accordance with Test Method D4716/D4716M; however, recent research has shown that TestMethod D4716/D4716M typically underestimates the actualflow rates at a certain hydraulic gradient (tested with alarge-scale transmissivimeter), at least for unidirectional drain-age geocomposites, and as a result
46、Test Method D4716/D4716M transmissivity results are typically conservative.6.2.3 Furthermore, standard engineering practice identifiesthat the transmissivity is only valid for laminar flow conditions,specifically when Darcys law is valid, and then the transmis-sivity is an intrinsic property of the
47、product and not dependenton external conditions such as the hydraulic gradient. Accord-ing to Darcys law, transmissivity should be a constant.However, transmissivity testing of drainage geocomposites hasshown that transmissivity is not a constant, but is associatednot only with the normal load but a
48、lso with the hydraulicgradient and selected boundary conditions. In fact, transmis-sivity decreases as the hydraulic gradient increases, because ofthe development of turbulent flow conditions within the waterpath of the product being tested. Typically, for hydraulicgradients used in transmissivity t
49、ests (greater than 0.1), theflow is non-laminar for drainage geonets or drainage geonetgeocomposites (Giroud et al., 2012). Therefore, the water flowrate of a drainage geocomposite can be better expressed as adischarge (flow rate) at a given hydraulic loss (van der Sluysand Dierickx, 1987) than as a transmissivity.46.3 Reduction Factor for CreepThis is a long-term (typi-cally 10 000 h) compressive load test focused on the stabilityor deformation (or both) of the drainage core without thecovering geotextiles. Stress orientation can be perpendicular orat an an
