1、Designation: D 5262 07Standard Test Method forEvaluating the Unconfined Tension Creep and CreepRupture Behavior of Geosynthetics1This standard is issued under the fixed designation D 5262; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revi
2、sion, the year 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. Scope1.1 This test method is intended for use in determining theunconfined tension creep and creep rupture b
3、ehavior of geo-synthetics at constant temperature when subjected to a sus-tained tensile loading. This test method is applicable to allgeosynthetics.1.2 The test method measures total elongation of the geo-synthetic test specimen, from the time of loading, while beingmaintained at a constant tempera
4、ture. It includes proceduresfor measuring the tension creep and creep rupture behavior atconstant temperature of conditioned geosynthetics as well asdirections for calculating tension creep and creep rupturecurves.1.3 The values stated in SI units are to be regarded as thestandard. The values given
5、in parentheses are for informationonly.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 determine the applica-bility of regulatory l
6、imitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 123 Terminology Relating to TextilesD 1776 Practice for Conditioning and Testing TextilesD 2990 Test Methods for Tensile, Compressive, and Flex-ural Creep and Creep-Rupture of PlasticsD 4354 Practice for Sampling of Geosynthetics f
7、or TestingD 4439 Terminology for GeosyntheticsD 4491 Test Methods for Water Permeability of Geotextilesby PermittivityD 4595 Test Method for Tensile Properties of Geotextilesby the Wide-Width Strip MethodD 6637 Test Method for Determining Tensile Properties ofGeogrids by the Single or Multi-Rib Tens
8、ile MethodE6 Terminology Relating to Methods of Mechanical Test-ing3. Terminology3.1 DefinitionsFor definitions of many terms used in thistest method, refer to Terminologies D 123, D 4439 and E6.3.2 Definitions of Terms Specific to This Standard:3.2.1 atmosphere for testing geosynthetics, nair main-
9、tained at a relative humidity between 50 and 70 % and the test(Section 10.2).3.2.2 creep, nthe time-dependent increase in accumula-tive strain in a material resulting from an applied constantforce.3.2.3 design load, nthe load at which the geosynthetic isrequired to operate in order to perform its in
10、tended function.3.2.4 failure, nan arbitrary point at which a materialceases to be functionally capable of its intended use.3.2.5 geogrid, na geosynthetic formed by a regular net-work of integrally connected elements with apertures greaterthan 6.35 mm (14 in.) to allow interlocking with surroundings
11、oil, rock, earth, and other surrounding materials to functionprimarily as reinforcement.3.2.6 geomembrane, nan essentially impermeable geo-synthetic composed of one or more synthetic sheets.3.2.6.1 DiscussionIn geotechnical engineering, essen-tially impermeable means that no measurable liquid flowst
12、hrough a geosynthetic when tested in accordance with TestMethods D 4491.3.2.7 geosynthetic, na planar product manufactured frompolymeric material used with soil, rock, earth, or other geo-technical engineering-related material as an integral part of aman-made project, structure, or system.3.2.8 geot
13、extile, na permeable geosynthetic comprisedsolely of textiles.1This test method is under the jurisdiction of ASTM Committee D35 onGeosynthetics and is the direct responsibility of Subcommittee D35.02 on Endur-ance Properties.Current edition approved June 1, 2007. Published August 2007. Originallyapp
14、roved in 1992. Last previous edition approved in 2006 as D 5262 06.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandardsvolume information, refer to the standardss Document Summary page onthe ASTM we
15、bsite.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.2.8.1 DiscussionCurrent manufacturing techniques pro-duce nonwoven fabrics, knitted (non-tubular) fabrics, andwoven fabrics.3.2.9 index test, na test procedure that may contain
16、aknown bias, but that may be used to establish an order for a setof specimens with respect to the property being measured.3.2.10 rate of creep, nthe slope of the creep-time curve ata given time.3.2.11 tensile creep rupture strength, FL1, nfor geo-synthetics, the force per unit width that will produc
17、e failure byrupture in a creep test in a given time, at a specified constantenvironment.3.2.12 tensile creep strain, nthe total strain at any giventime.3.2.13 wide strip tensile test, nfor geosynthetics, a tensiletest in which the entire width of a 200-mm (8.0 in.)-widespecimen is gripped in the cla
18、mps with a gage length of 100mm (4.0 in.).4. Summary of Test Method4.1 The tension creep and creep rupture behavior of geo-synthetics is measured by applying a sustained load in one stepand measuring the total elongation of the test specimen as afunction of time while maintaining a specified tempera
19、ture andhumidity.5. Significance and Use5.1 This test method is developed for use in the determina-tion of anticipated total elongation or time to rupture that mayoccur in geosynthetics under sustained loading conditions.5.1.1 The test data can be used in conjunction with inter-pretive methods to ev
20、aluate creep strain potential at designloads.5.1.2 The test data can be used in conjunction with inter-pretive methods to evaluate creep rupture potential at variousloads.5.2 This test method is not intended for routine acceptancetesting of geosynthetics. This test method should be used tocharacteri
21、ze geosynthetics intended for use in applications inwhich creep or creep rupture is of concern. The plane strain orrupture condition imposed during testing must be consideredwhen using the test results for design.5.3 The basic distinctions between this test method andother test methods for measuring
22、 tension creep and creeprupture behavior are (1) the width of the specimens (Section 8)and (2) the measurement of total elongation or time to rupturefrom the moment of specimen loading. The greater widths ofthe specimens specified in this test method minimize thecontraction edge effect (necking) tha
23、t occurs in many geosyn-thetic materials and provides a closer relationship to actualmaterial behavior in plane strain tension conditions.5.4 The creep or stress rupture of a given geosynthetic islikely to be reduced in soil because of load transfer to the soil.The unconfined environment represents
24、a controlled test, inwhich the results are conservative with regard to the behaviorof the material in service. Confined or in-soil testing maymodel the field behavior of the geosynthetic more accurately.6. Apparatus6.1 Clamps:6.1.1 Clamps should be at least as wide as the specimen,with appropriate c
25、lamping power that will prevent slipping ordamage of the test specimen within or at the faces of theclamps. The clamps and clamping technique shall be designedto minimize eccentric loading of the specimen. A swivel oruniversal joint shall be used on one of the clamps at the end ofthe specimen. It is
26、 recommended that clamps permit the finalcentering of the specimen prior to application of the load.36.1.2 Geotextiles and GeomembranesEach clamp shall besufficiently wide to grip the entire width of the specimen, 200mm (8.0 in.), and a minimum of 50-mm (2.0-in.) length in thedirection of the applie
27、d force.6.1.3 GeogridsThese should be clamped to assure com-plete tension load transfer through test direction members. Thetype of clamp and load transfer mechanism should be detailedin the test report. Roller grips or low melting point alloy withadequate strength may be used to assist proper clampi
28、ng.6.1.4 Other Related ProductsWhere special clamps areused to grip these products, they should conform to the generalrequirements for clamps used to grip geotextiles, geomem-branes, and geogrids, and the clamping methods used shouldalways be detailed in the report.6.2 Loading SystemThe loading syst
29、em must be designedso that the load applied and maintained on the specimen iswithin 61 % of the desired load. Loads may be applied byweights, weights and fulcrums, or pneumatics. The loadingmechanism must permit reproducibly rapid and smooth load-ing, as specified in 11.4. No dynamic forces on place
30、ment ofthe loads shall be allowed. Provision must also be made toensure that shock loading, caused by specimen failure, is nottransferred to other specimens undergoing testing.36.3 Extension MeasurementExtensometers are preferredfor the measurement of elongation in geosynthetics. Wheneverpossible, o
31、ther means of measuring elongation should becalibrated against extensometers. In any case, the devicechosen shall be capable of measuring deformations to anaccuracy of at least 0.003 6 mm (0.0001 6 in.). The means ofmeasuring elongation should be indicated clearly in the report.6.4 Vibration Control
32、Creep and creep rupture tests aresensitive to shock and vibration. The location of the apparatus,test equipment, and mounting shall be designed so that thespecimen is isolated from vibration. Multi-station test equip-ment must be of sufficient rigidity so that no significantdeflection due to shock o
33、r vibration occurs during testing.6.5 Time MeasurementThe accuracy of the time measur-ing device shall be 61 % of the elapsed time of each creep orcreep rupture measurement load increment.6.6 Temperature Control and Measurement:6.6.1 The temperature in the test space, especially close tothe gage len
34、gth of the specimen, shall be maintained within62.0C (63.6F) of the targeted value by a suitable automaticdevice and shall be stated in the report. It is generallyrecognized that thermal contraction and expansion, associated3Examples of clamping, loading, and extensometer systems that have been used
35、successfully are found in the appendixes.D5262072with small temperature changes during the test, may producechanges in the apparent creep rate, especially near the transi-tion temperature.6.6.2 Temperature measurements shall be recorded at fre-quent intervals, or recorded continuously, in order to e
36、nsure anaccurate determination of the average test temperature andcompliance with 6.6.1.6.7 Environmental Control and Measurement:6.7.1 When the test environment is air, the relative humidityshall be maintained between 50 and 70 % unless the creep orcreep rupture behavior of the geosynthetic has bee
37、n shown tobe unaffected by humidity. The relative humidity shall berecorded at frequent intervals to ensure that an accuratedetermination of the average test humidity can be made.6.7.2 The test environment shall be maintained constantthroughout the test. Safety precautions should be taken to avoidpe
38、rsonal contact during the test. The area should be isolatedadequately and fenced such that only the test operator hasaccess to the test station.7. Sampling7.1 Laboratory SampleFor the laboratory sample, take afull-width swatch at least 1-m (40-in.) long in the machinedirection from each roll in the
39、lot sample. The sample may betaken from the end portion of a roll, provided there is noevidence that it is different from other portions of the roll.7.2 Test Specimens:7.2.1 Geotextiles and GeomembranesFor tests in themachine and cross-machine directions, respectively, take fromeach sample the numbe
40、r of specimens as directed in 9.1. Takethe specimens from a diagonal on the sample, with nospecimens closer than110 the width of the roll or 150 mm (6in.), whichever is smaller. For geomembranes, exercise care inselecting, cutting, and preparing the specimens to avoid nicks,tears, scratches, folds,
41、or other imperfections that are likely tocause premature failure.NOTE 1Nonreinforced geomembranes are extremely sensitive in thisregard.7.2.2 Geogrids and Other Related ProductsFor tests inthe machine and cross-machine directions, respectively, takefrom each sample the number of specimens as directe
42、d in 9.1.Take the specimens at random from the laboratory sample. Formeasurement of machine direction properties, take specimensfrom different positions across the width of the sample. For themeasurement of cross-machine direction properties, take speci-mens from different positions along the length
43、 of the sample.Take no specimens nearer to the edge than1/10 the width of theroll or 150 mm (6 in.), whichever is smaller.8. Test Specimen8.1 GeosyntheticsPrepare each finished specimen tospecimen to the width appropriate for the particular geosyn-thetic with the length dimension parallel to the dir
44、ection thatthe creep or creep rupture behavior is being measured.8.1.1 GeotextilesPrepare specimen width to 200 mm (8.0in) wide by at least 200 mm (8.0 in) long.8.1.2 GeogridsPrepare specimen width to include at leastthree longitudinal elements abreast parallel to the direction thatthe creep or cree
45、p rupture behavior is being measured witheach element long enough to include at least three apertures, asillustrated in Fig. X2.1.8.2 The length of the specimen depends on the type ofclamps being used. The specimen must be long enough toextend through the full length of both clamps, as determinedfor
46、 the direction of the test.8.3 When specimen integrity is not affected, the specimenmay be cut initially to the finished width.8.4 This test method may not be suitable for some wovengeotextiles or geogrids that exhibit breaking strengths in excessof 100 kN/m (570 lbf/in.), due to clamping and equipm
47、entlimitations.9. Number of Tests9.1 Unless otherwise agreed upon, creep and creep rupturetests shall be conducted at load levels as specified by thedesigner. Four load levels are recommended for characteriza-tion of the material. Loads shall be selected at intervals ofapproximately 10 % of the maxi
48、mum load per unit width asdetermined by applicable ASTM test methods.9.1.1 For creep test, the loads should be 20, 30, 40, 50 and60 % of the ultimate tensile strength of the sample being tested,unless otherwise agreed upon by the parties involved.9.1.2 For creep rupture tests, the loads should be 50
49、, 60, 70,80, and 90 % of the ultimate tensile strength of the samplebeing tested, unless otherwise agreed upon by the partiesinvolved.NOTE 2It is generally recognized that characterization involves iden-tification of the load levels at which there is no creep (no increase in strainwith the log of time), low to moderate creep (linear increase in strain withthe log of time), and high creep (exponential increase in strain with the logof time).9.2 To evaluate design creep strains, it is recommended thata minimum of two creep tests be performed for ea
