1、Designation: D532108 D5321/D5321M13 Standard Test Method for Determining the Coefficient Shear Strength of Soil and Geosynthetic or Geosynthetic and Geosynthetic Friction by the Direct Shear MethodSoil-Geosynthetic and Geosynthetic-Geosynthetic Interfaces by Direct Shear 1 Thisstandardisissuedundert
2、hexeddesignationD5321;D5321/D5321M;thenumberimmediatelyfollowingthedesignationindicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon () indicates an editorial change since th
3、e last revision or reapproval. NoteEditorial corrections were made to the units information, Section 3, and throughout the standard onAugust 23, 2013. 1. Scope 1.1 This test method covers a procedure for determining the shear resistance of a geosynthetic against soil, or a geosynthetic against anoth
4、er geosynthetic, under a constant rate of deformation. 1.1.1 The test method is intended to indicate the performance of the selected specimen by attempting to model certain eld conditions. Results obtained from this method may be limited in their applicability to the specic conditions considered in
5、the testing. 1.2 The test method is applicable for all geosynthetics. geosynthetics, with the exception of geosynthetic clay liners (GCLs) which are addressed in Test Method D6243/D6243M. 1.3 The test method is not suited for the development of exact stress-strain relationships for the test specimen
6、 due to the non-uniform distribution of shearing forces and displacement. 1.4 The values stated in either SI units or inch-pound units are to be regarded separately as the standard. The values given in parentheses are for information only. stated in each system may not be exact equivalents; therefor
7、e, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard. 1.5 This standard does not purport to address all the safety concerns, if any, associated with its use. It is the responsibility of the user of this standar
8、d to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 2. Referenced Documents 2.1 ASTM Standards: 2 D653Terminology Relating to Soil, Rock, and Contained Fluids D698Test Methods for Laboratory Compaction Characteristics of Soil
9、 Using Standard Effort (12 400 ft-lbf/ft 3 (600 kN-m/m 3 ) D1557Test Methods for Laboratory Compaction Characteristics of Soil Using Modied Effort (56,000 ft-lbf/ft 3 (2,700 kN-m/m 3 ) D2435D2435/D2435MTest Methods for One-Dimensional Consolidation Properties of Soils Using Incremental Loading D2487
10、Practice for Classication of Soils for Engineering Purposes (Unied Soil Classication System) D3080D3080/D3080MTest Method for Direct Shear Test of Soils Under Consolidated Drained Conditions D3740Practice for Minimum Requirements for Agencies Engaged in Testing and/or Inspection of Soil and Rock as
11、Used in Engineering Design and Construction D4354Practice for Sampling of Geosynthetics and Rolled Erosion Control Products(RECPs) for Testing D4439Terminology for Geosynthetics D6243/D6243MTestMethodforDeterminingtheInternalandInterfaceShearStrengthofGeosyntheticClayLinerbytheDirect Shear Method 1
12、ThistestmethodisunderthejurisdictionofASTMCommitteeD35onGeosyntheticsandisthedirectresponsibilityofSubcommitteeD35.01onMechanicalProperties. Current edition approved July 1, 2008Aug. 23, 2013. Published August 2008September 2013. Originally approved in 1992. Last previous edition approved in 2002201
13、2 as D53210212 DOI: 10.1520/D5321-08.10.1520/D5321_D5321M-13. 2 ForreferencedASTMstandards,visittheASTMwebsite,www.astm.org,orcontactASTMCustomerServiceatserviceastm.org.ForAnnualBookofASTMStandards volume information, refer to the standards Document Summary page on the ASTM website. This document i
14、s not anASTM standard and is intended only to provide the user of anASTM standard an indication of what changes have been made to the previous version. Because it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropr
15、iate. In all cases only the current version of the standard as published by ASTM is to be considered the official document. Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA19428-2959. United States 13. Terminology 3.1 Denitions: For denitions of terms relating
16、to soil and rock, refer to Terminology D653. For denitions of terms relating to geosynthetics, refer to Terminology D4439. 3.2 Denitions of Terms Specic to This Standard: 3.2.1 adhesion, c a n the shearing resistance between two adjacent materials under zero normal stress. Practically, this is deter
17、mined as the y-intercept of a straight line relating the limiting value of shear stress that resist slippage between two materials and the normal stress across the contact surface of the two materials. (D653, D-18) 3.2.1 angleofadhesion,c a friction,n(angleoffrictionbetweentwomaterials)(degrees)thea
18、nglewhosetangentistheslope of the line relating limiting value of the shear stress that resists slippage between two solid bodies and the normal stress across the contact surface of the two bodies. Limiting value may be at the peak shear stress or at some other failure condition dened bytheuserofthe
19、testresults.Thisiscommonlyreferredtoasinterfacefrictionangle.they-interceptoftheMohr-Coulombstrength envelope. (D653, D-18) 3.2.2 atmosphere for testing geosynthetics, nair maintained at a relative humidity of 6565% and temperature of 2162C (7064F). between 50 and 70% and temperature of 21 6 2C 70 6
20、 4F. (D4439) 3.2.3 coeffcient of friction, Mohr-Coulomb friction angle, d, nThe slope of the line relating limiting value (angle of friction of a material or between two materials, ) the angle dened by the least-squares, best-t straight line through a dened section of the shear stress that resists s
21、lippage between two materials and the normal stress across the contact surface of the two bodies. Limiting value may be at the peak shear stress or at some other failure condition dened by the user.strength-normal stress failure envelope; the component of the shear strength indicated by the term d,
22、in Coulombs equation, t = c a + s n * tan (d ) (see 12.6). 3.2.3.1 Discussion The end user is cautioned that some organizations (for example, FHWA, AASHTO along with state agencies who use these documents) are currently using the Greek letter, Delta (d), to designate wall-backll interface friction a
23、ngle and the Greek letter, Rho (r), to designate the interface friction angle between geosynthetics and soil. 3,4 (D653, D-18) 3.2.4 directMohr-Coulomb shear friction test,strength envelope, nfor geosynthetics, a procedure in which the interface betweenageosyntheticandanyothersurface,underarangeofno
24、rmalstressesspeciedbytheuser,isstressedtotheleastsquares, best t straight line through a dened section of the shear strength-normal stress failure envelope described by the equation, t = c a + s n * tan (d ) (see 12.6failure by the horizontal movement of one surface against the other. ).The envelope
25、 can be described for any chosen shear failure mode (example, peak or post-peak). 3.2.5 geosynthetic, secant friction angle, d sec , na planar synthetic product manufactured from polymeric material used with soil, rock, earth, or other geotechnical engineering-related material as an integral part of
26、 a man-made project, structure, or system. (angle of friction of a material or between two materials, ) the angle dened by a line drawn from the origin to a data point on the shear strength-normal stress failure envelope. Intended to be used only for the normal stress on the shearing plane for which
27、 it is dened. (D4439) 3.2.6 limitingvalue,shearstrength,t,nthevalueofshearstressatsomecondition,suchasthepeakvalue,theultimatevalue, or the value at some prescribed displacement.shear force on a given failure plane. In the direct shear test it is always stated in relation to the normal stress acting
28、 on the failure plane. Two different types of shear strengths are often estimated and used in standard practice: 3.2.6.1 peak shear strengththe largest value of shear resistance experienced during the test under a given normal stress. 3.2.6.2 post-peak shear strengththe minimum, or steady-state valu
29、e of shear resistance that occurs after the peak shear strength is experienced. 3.2.6.3 Discussion Theenduseriscautionedthatthereportedvalueofpost-peakshearstrength(regardlesshowdened)isnotnecessarilytheresidual shear strength. In some instances, a post-peak shear strength may not be dened before th
30、e limit of horizontal displacement is reached. 3.2.7 shear strength envelope, ncurvi-linear line on the shear stress-normal stress plot representing the combination of shear and normal stresses that dene a selected shear failure mode (for example, peak and post-peak). 3 LRFD Bridge Design Specicatio
31、ns, 5th Edition, American Association of State Highway and Transportation Officials (AASHTO), Washington, D.C., 2010. 4 Mechanically Stabilized Earth Walls and Reinforced Soil Slopes, Design and Construction Guidelines,FHWA GEC 011, FHWA NHI-10-024, Vol I, and FHWA NHI-10-025, Vol II, U.S. Departmen
32、t of Transportation, Federal Highway Administration (FHWA), Washington, D.C., 2009. D5321/D5321M 13 24. Summary of Test Method 4.1 The shear resistance between a geosynthetic and a soil, or other material selected by the user, is determined by placing the geosyntheticandoneormorecontactsurfaces,such
33、assoil,withinadirectshearbox.Aconstantnormalforcestressrepresentative of design stresses is applied to the specimen, and a tangential (shear) force is applied to the apparatus so that one section of the box moves in relation to the other section. The shear force is recorded as a function of the hori
34、zontalshear displacement of the moving section of the shear box. 4.2 ThetestisperformedatTodeneaMohr-Coulombshearstrengthenvelope,itisrecommendedthataminimumofthreetest points be performed at different normal stresses, selected by the user, to model appropriate eld conditions. However, there may bei
35、nstanceswherefewertestpointsaredesired(seeNote1Thelimitingvaluesofshearstresses).Thepeakshearstresses,orshear stresses at some post-peak displacement, or both, are plotted against the applied normal compressive stresses used for testing.The test data are generally represented by a best t straight li
36、ne through the peak strength values whose slope is the coefficient of friction Mohr-Coulomb friction angle for peak strength between the two materials where the shearing occurred. The y-intercept of the straight line is the adhesion.adhesion intercept. A straight line t for shear stresses at some po
37、st-peak displacement is the post-peak interface strength between the two materials where the shearing occurred. NOTE 1There may be some investigative cases where only a single test point is desired. If the eld design conditions will experience a range of normal stresses, it is standard industry prac
38、tice to bracket the normal-stress range with tests on both sides of the range, as it is unconservative to extrapolate results outside of the normal-stress range tested. When dening a Mohr-Coulomb shear strength envelope over a range of normal stresses, standard industry practice is to use a minimum
39、of three test points. Attempting to dene a single linear Mohr-Coulomb shear strength envelope over too-large of a normal-stress range may prove to be problematic in many cases because most failure envelopes exhibit signicant curvature over such a large range, particularly at low normal stresses on t
40、he shearing plane. 5. Signicance and Use 5.1 Theproceduredescribedinthistestmethodfordeterminationofthecoefficientshearresistanceofthesoilandgeosynthetic or geosynthetic and geosynthetic friction by the direct shear method interface is intended as a performance test to provide the user with a set of
41、 design values for the test conditions examined. The test specimens and conditions, including normal stresses, are generally selected by the user. 5.2 This test method may be used for acceptance testing of commercial shipments of geosynthetics, but caution is advised as outlined below.in 5.2.1. 5.2.
42、1 The coefficient of soil and geosynthetic friction shear resistance can be expressed only in terms of the soil used in testing actualtestconditions(seeNote12andNote23).Thedeterminedvaluemaybeafunctionoftheappliednormalstress,geosynthetic material characteristics, soil gradation, soil plasticity, de
43、nsity, moisture content,material characteristics (for example, of the geosynthetic),soilproperties,sizeofsample,moisturecontent,drainageconditions,displacementrate,magnitudeofdisplacement, and other parameters. NOTE 2In the case of acceptance testing requiring the use of soil, the user must furnish
44、the soil sample, soil parameters, and direct shear test parameters. The method of test data interpretation for purposes of acceptance should be mutually agreed to by the users of this test method. NOTE 3Testing under this standard test method should be performed by laboratories experiencedqualied in
45、 the direct shear testing of soils and meeting the requirements of Practice D3740, especially since the test results may depend on site-specic and test conditions. 5.2.2 This test method measures the total resistance to shear between a geosynthetic and a supporting material (substratum) or a geosynt
46、hetic and an overlying material (superstratum). Total sliding The total shear resistance may be a combination of sliding, rolling, interlocking of soil particles and geosynthetic surfaces, and shear strain within the geosynthetic specimen. Shearing resistance may be different on the two faces of a g
47、eosynthetic and may vary with direction of shearing relative to orientation of the geosynthetic. rolling and interlocking of material components. 5.2.3 TheThis test method does not distinguish between individual mechanisms, which may be a function of the soil and geosynthetic used, method of soil pl
48、acement, material placement and hydration, normal and shear stresses applied, rate of horizontalmeans used to hold the geosynthetic in place, rate of shear displacement, and other factors. Every effort should be made to identify and record with a sketch, identify, as closely as is practicable, the s
49、heared area and failure mode of the specimen. Care should be taken, including close visual inspection of the specimen after testing, to ensure that the testing conditions are representative of those being investigated. 5.2.4 Information on precision betweenamong laboratories is incomplete. In cases of dispute, comparative tests to determine whether a statistical bias exists betweenamong laboratories may be advisable. 5.3 The test method produces test data that results can be used in the design of geosyntheic app
