ASTM D6706-2001(2013) 7500 Standard Test Method for Measuring Geosynthetic Pullout Resistance in Soil《测量土壤中土工合成材料拉拔力的标准试验方法》.pdf

《ASTM D6706-2001(2013) 7500 Standard Test Method for Measuring Geosynthetic Pullout Resistance in Soil《测量土壤中土工合成材料拉拔力的标准试验方法》.pdf》由会员分享，可在线阅读，更多相关《ASTM D6706-2001(2013) 7500 Standard Test Method for Measuring Geosynthetic Pullout Resistance in Soil《测量土壤中土工合成材料拉拔力的标准试验方法》.pdf（8页珍藏版）》请在麦多课文档分享上搜索。

1、Designation: D6706 01 (Reapproved 2013)Standard Test Method forMeasuring Geosynthetic Pullout Resistance in Soil1This standard is issued under the fixed designation D6706; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of

2、 last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 Resistance of a geosynthetic to pullout from soil isdetermined using a laboratory pullout box.1.2 The test method is

3、intended to be a performance testconducted as closely as possible to replicate design or as-builtconditions. It can also be used to compare differentgeosynthetics, soil types, etc., and thereby be used as a researchand development test procedure.1.3 The values stated in SI units are to be regarded a

4、sstandard. The values stated in parentheses are provided forinformation only.1.4 This standard may involve hazardous materials, andequipment. 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

5、establish appro-priate safety and health practices and determine 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 ContainedFluidsD3080 Test Method for Direct Shear Te

6、st of Soils UnderConsolidated Drained ConditionsD4354 Practice for Sampling of Geosynthetics and RolledErosion Control Products(RECPs) for TestingD4439 Terminology for Geosynthetics3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 apertures, nthe open spaces in geogrids whichena

7、ble soil interlocking to occur.3.1.2 atmosphere for testing geosynthetics, nair main-tained at a relative humidity of 60 6 10 % and a temperatureof 21 6 2C (70 6 4F).3.1.3 cross-machine direction, nthe direction in the planeof the geosynthetic perpendicular to the direction of manufac-ture.3.1.4 fai

8、lure, na defined point at which a material ceasesto be functionally capable of its intended use.3.1.5 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, structu

9、re, or system. (D4439)3.1.6 junction, nthe point where geogrid ribs are intercon-nected in order to provide structure and dimensional stability.3.1.7 machine direction, nthe direction in the plane of thegeosynthetic parallel to the direction of manufacture.3.1.8 pullout, nthe movement of a geosynthe

10、tic over itsentire embedded length, with initial pullout occurring when theback of the specimen moves, and ultimate pullout occurringwhen the movement is uniform over the entire embeddedlength.3.1.9 pullout force, (kN),nforce required to pull a geo-synthetic out of the soil during a pullout test.3.1

11、.10 pullout resistance, (kN/m),nthe pullout force perwidth of geosynthetic measured at a specified condition ofdisplacement.3.1.11 rib, nthe continuous elements of a geogrid whichare either in the machine or cross-machine direction asmanufactured.3.1.12 ultimate pullout resistance, (kN/m),nthe maxi-

12、mum pullout resistance measured during a pullout test.3.1.13 wire gage, na displacement gage consisting of anon extensible wire attached to the geosynthetic and monitoredby connection to a dial extensometer, or electronic displace-ment transducer.3.2 For definitions of other terms used in this test

13、methodrefer to Terminology D123, D653, and D4439.1This test method is under the jurisdiction of ASTM Committee D35 onGeosynthetics and is the direct responsibility of Subcommittee D35.01 on Mechani-cal Properties.Current edition approved Jan. 1, 2013. Published January 2013. Originallyapproved in 20

14、01. Last previous edition approved in 2007 as D670601(2007).DOI: 10.1520/D6706-01R13.2For 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

15、page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14. Summary of Test Method4.1 In this method, a geosynthetic is embedded between twolayers of soil, horizontal force is applied to the geosyntheticand the force re

16、quired to pull the geosynthetic out of the soil isrecorded.4.2 Pullout resistance is obtained by dividing the maximumload by the test specimen width.4.3 The test is performed while subjected to normal com-pressive stresses which are applied to the top soil layer.4.4 A plot of maximum pullout resista

17、nce versus appliednormal stress is obtained by conducting a series of such tests.5. Significance and Use5.1 The pullout test method is intended as a performancetest to provide the user with a set of design values for the testconditions examined.5.1.1 The test method is applicable to all geosynthetic

18、s andall soils.5.1.2 This test method produces test data, which can be usedin the design of geosynthetic-reinforced retaining walls, slopes,and embankments, or in other applications where resistance ofa geosynthetic to pullout under simulated field conditions isimportant.5.1.3 The test results may a

19、lso provide information relatedto the in-soil stress-strain response of a geosynthetic underconfined loading conditions.5.2 The pullout resistance versus normal stress plot obtainedfrom this test is a function of soil gradation, plasticity,as-placed dry unit weight, moisture content, length and surf

20、acecharacteristics of the geosynthetic and other test parameters.Therefore, results are expressed in terms of the actual testconditions. The test measures the net effect of a combination ofpullout mechanisms, which may vary depending on type ofgeosynthetic specimen, embedment length, relative openin

21、gsize, soil type, displacement rate, normal stress, and otherfactors.5.3 Information between laboratories on precision is incom-plete. In cases of dispute, comparative tests to determine ifthere is a statistical bias between laboratories may be advis-able.6. Apparatus6.1 Pullout BoxAn open rigid box

22、 consisting of twosmooth parallel sides, a back wall, a horizontal split removabledoor, a bottom plate, and a load transfer sleeve. The door is atthe front as defined by the direction of applied pullout force. Atypical box is shown in Fig. 1.6.1.1 The box should be square or rectangular with mini-mu

23、m dimensions 610 mm (24 in.) long by 460 mm (18 in.)wide by 305 mm (12 in.) deep, if sidewall friction isminimized, otherwise the minimum width should be 760 mm(30 in.). The dimensions should be increased, if necessary, sothat minimum width is the greater of 20 times the D85 of thesoil or 6 times th

24、e maximum soil particle size, and theminimum length greater than 5 times the maximum geosyn-thetic aperture size. The box shall allow for a minimum depthof 150 mm (6 in.) above and below the geosynthetic. The depthof the soil in the box above or below the geosynthetic shall bea minimum of 6 times th

25、e D85 of the soil or 3 times themaximum particle size of the soil, whichever is greater. Thebox must allow for at least 610 mm (24 in.) embedment lengthbeyond the load transfer sleeve and a minimum specimenlength to width ratio of 2.0. It should be understood that whentesting large aperture geosynth

26、etics the actual pullout box mayhave to be larger than the stated minimum dimensions.NOTE 1To remove side wall friction as much as possible a highdensity polyethylene (HDPE) geomembrane should be bonded to theFIG. 1 Experimental Set-Up for Geosynthetic Pullout TestingD6706 01 (2013)2inside surfaces

27、of the pullout box. The sidewalls may also be covered witha layer of silk fabric, which has been shown to eliminate adhesion and hasa very low friction value. Alternatively, a lubricant can be spread on thesidewalls of the box and thin sheets of polyethylene film used to minimizethe side wall fricti

28、on. It should be also noted that the effect of sidewallfriction on the soil-geosynthetic interface can also be eliminated if aminimum distance is kept between the specimen and the side wall. Thisminimum distance is recommended to be 150 mm (6 in.).6.1.2 The box shall be fitted with a metal sleeve at

29、 theentrance of the box to transfer the force into the soil to asufficient horizontal distance so as to significantly reduce thestress on the door of the box. The sleeve, as shown in Fig. 2,shall consist of two thin plates (no more than 13 mm (0.5 in.)thick) extending the full width of the pullout b

30、ox and into thepullout box a minimum distance of 150 mm (6 in.) but it isrecommended that this distance equal the total soil depth aboveor below the geosynthetic. The plates shall be tapered as shownin Fig. 2, such that at the point of load application in the soil,the plates forming the sleeve are n

31、o more then 3 mm (0.12 in.)thick. The plates shall be rigidly separated at the sides withspacers and be sufficiently stiff such that normal stress is nottransferred to the geosynthetic between the plates.6.2 Normal Stress Loading DeviceNormal stress appliedto the upper layer of soil above the geosyn

32、thetic must beconstant and uniform for the duration of the test. To maintaina uniform normal stress, a flexible pneumatic or hydraulicdiaphragm-loading device which is continuous over the entirepullout box area should be used and capable of maintaining theapplied normal stress within 62 % of the req

33、uired normalstress. Normal stresses utilized will depend on testingrequirements, however, stresses up to 250 kPa (35 psi) shouldbe anticipated.Arecommended normal stress-loading device isan air bag is shown in Fig. 2.6.3 Pullout Force Loading DevicePullout force must besupplied by a device with the

34、ability to pull the geosynthetichorizontally out of the pullout box. The force must be at thesame level with the specimen. The pullout system must be ableto apply the pullout force at a constant rate of displacement,slow enough to dissipate soil pore pressures as outlined in TestMethod D3080. If exc

35、ess pore pressures are not anticipated andin the absence of a material specification, apply the pulloutforce at a rate of 1 mm/min 610 percent, and the pullout rateshould be monitored during testing, see Note 2. Also, a deviceto measure the pullout force such as a load cell or proving ringmust be in

36、corporated into the system and shall be accuratewithin 60.5 % of its full-scale range.NOTE 2Pullout tests may also be conducted using a constant stressloading approach. This approach can be achieved using one of the threemethods described: (1) Controlled Stress Rate Method (short-term loadingconditi

37、on) where the pullout force is applied to the geosynthetic under auniform rate of load application, not exceeding 2 kN/m/min until pulloutor failure of the geosynthetic is achieved; (2) Incremental Stress Method(short-term loading condition) where the pullout force is applied inuniform or doubling i

38、ncrements and held for a specific time beforeproceeding to the next increment, as agreed to by the parties involved untilpullout or failure of the geosynthetic is achieved; and (3) Constant Stress(Creep) Method (long-term loading condition) where the pullout force isapplied using one of the first tw

39、o methods mentioned above to achieve therequired constant stress for the test. The constant stress is maintained andthe test specimen is monitored over time for the duration of time agreedto by the parties involved (i.e., typically 100 to 10,000 h depending onFIG. 2 Cross-Sectional Detail View for G

40、eosynthetic Pullout SetupD6706 01 (2013)3application). It should be noted that the constant stress proceduresdescribed above, have not been widely researched and comparisons withthe constant strain method have not been determined.6.4 Displacement IndicatorsHorizontal displacement ofthe geosynthetic

41、is measured at the entrance of the pullout boxand at several locations on the embedded portion of thespecimen. Measurements outside the door at the pullout boxentrance are made by a dial extensometer or electronic dis-placement transducers (e.g. liner variable differential trans-formers (LVDTs) can

42、be used) mounted to the box frame toread against a plate attached to the specimen near the door.6.4.1 Determine the displacement of the geosynthetic at aminimum of three equally spaced distances from the clampingplates. Displacement measurements within the box may em-ploy any of several methods, whi

43、ch place sensors or gaugeconnectors directly on the geosynthetic and monitor theirchange in location remotely. One such device utilizes wiregages, which are protected from normal stress by a surroundingtube, which runs from a location mounted on the specimen tothe outside of the box where displaceme

44、nts are measured by adial indicator or electronic displacement transducer. A typicalinstrumentation setup is shown in Fig. 3.6.4.2 All dial gauges or electronic measurement devicesmust be accurate to 6 0.10 mm. Locations of the devices mustbe accurately determined and recorded. Minimum extensioncapa

45、bilities of 50 mm (2 in.) are recommended.6.5 Geosynthetic Clamping Devices Clamps which con-nect the specimen to the pullout force system without slipping,causing clamp breaks or weakening the material may be used,see Note 3. The clamps shall be swiveled to allow the pullingforces to be distributed

46、 evenly through out the width of thesample. The clamps must allow the specimen to remainhorizontal during loading and not interfere with the pullout/shear surface. Gluing, bonding, or otherwise molding of ageosynthetic within the clamp area is acceptable and recom-mended whenever slippage might occu

47、r.NOTE 3A suggested device is shown in Fig. 4 and includes a simpleclamp consisting of two, 100 mm (4 in.) wide metal angle pieces with aseries of bolts and nuts holding the material between them. One possiblemodification is the addition of a metal rod behind the back flange whichallows looping of t

48、he material around the rod and back into the clamp. Theuse of epoxy bonding within the clamp is generally recommended whenaccurate measurement of the geosynthetic displacements within the soilare required.6.6 Soil Preparation EquipmentUse equipment as neces-sary for the placement of soils at desired

49、 conditions. This mayinclude compaction devices such as vibratory or “jumping-jack” type compaction, or hand compaction hammers. Soilcontainer or hopper, leveling tools and soil placement/removaltools may be required.6.7 Miscellaneous EquipmentMeasurement and trimmingequipment as necessary for geosynthetic preparation, a timingdevice and soil property testing equipment if desired.7. Geosynthetic Sampling7.1 Lot SampleDivide the product into lots and for any lotto be tested, take the lot samples as directed in Practice D4354,see Note 4.NOTE 4Lots of geosy