1、Designation: D5321/D5321M 14D5321/D5321M 17Standard Test Method forDetermining the Shear Strength of Soil-Geosynthetic andGeosynthetic-Geosynthetic Interfaces by Direct Shear1This standard is issued under the fixed designation D5321/D5321M; the number immediately following the designation indicates
2、theyear of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of lastreapproval. A superscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers a procedure for determin
3、ing the shear resistance of a geosynthetic against soil, or a geosyntheticagainst another 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 fieldconditions. Results obtained from th
4、is method may be limited in their applicability to the specific conditions considered in thetesting.1.2 The test method is applicable for all geosynthetics, with the exception of geosynthetic clay liners (GCLs) which areaddressed in Test Method D6243/D6243M.1.3 The test method is not suited for the
5、development of exact stress-strain relationships for the test specimen due to thenon-uniformnonuniform 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 standard. The values stated in eachsystem may not be e
6、xact equivalents; therefore, each system shall be used independently of the other. Combining values from thetwo systems may result in non-conformancenonconformance 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 resp
7、onsibility ofthe user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.1.6 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in th
8、e Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D653 Terminology Relating to Soil, Rock, and Contained FluidsD698 Test Meth
9、ods for Laboratory Compaction Characteristics of Soil Using Standard Effort (12,400 ft-lbf/ft3 (600 kN-m/m3)D1557 Test Methods for Laboratory Compaction Characteristics of Soil Using Modified Effort (56,000 ft-lbf/ft3 (2,700kN-m/m3)D2435/D2435M Test Methods for One-Dimensional Consolidation Properti
10、es of Soils Using Incremental LoadingD2487 Practice for Classification of Soils for Engineering Purposes (Unified Soil Classification System)D3080/D3080M Test Method for Direct Shear Test of Soils Under Consolidated Drained ConditionsD3740 Practice for Minimum Requirements for Agencies Engaged in Te
11、sting and/or Inspection of Soil and Rock as Used inEngineering Design and ConstructionD4354 Practice for Sampling of Geosynthetics and Rolled Erosion Control Products (RECPs) for TestingD4439 Terminology for GeosyntheticsD6243/D6243M Test Method for Determining the Internal and Interface Shear Stren
12、gth of Geosynthetic Clay Liner by the DirectShear Method1 This test method is under the jurisdiction ofASTM Committee D35 on Geosynthetics and is the direct responsibility of Subcommittee D35.01 on Mechanical Properties.Current edition approved Jan. 1, 2014June 1, 2017. Published January 2014June 20
13、17. Originally approved in 1992. Last previous edition approved in 20132014 asD5321/D5321MD5321/D5321M 14.13 DOI: 10.1520/D5321_D5321M-14.10.1520/D5321_D5321M-17.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book o
14、f ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technical
15、ly possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C
16、700, West Conshohocken, PA 19428-2959. United States13. Terminology3.1 Definitions:3.1.1 For definitions of terms relating to soil and rock, refer to Terminology D653. For definitions of terms relating togeosynthetics, refer to Terminology D4439.For definitions of terms relating to soil and rock, re
17、fer to Terminology D653. Fordefinitions of terms relating to geosynthetics, refer to Terminology D4439.3.2 Definitions of Terms Specific to This Standard:3.2.1 adhesion, ca, nthe y-intercepty-intercept of the Mohr-Coulomb strength envelope.3.2.2 atmosphere for testing geosynthetics, nair maintained
18、at a relative humidity between 50 and 70 % and a temperature of21 6 2C2 C 70 6 4F.4 F.3.2.3 Mohr-Coulomb friction angle, , n(angle of friction of a material or between two materials, ) the angle defined by theleast-squares, “best-fit” straight line through a defined section of the shear strength-nor
19、mal stress failure envelope; the componentof the shear strength indicated by the term , in Coulombs equation, = ca + n * tan ( ) (see 12.6).3.2.3.1 DiscussionThe end user is cautioned that some organizations (for example, FHWA, AASHTO, along with state agencies who use thesedocuments) are currently
20、using the Greek letter, Delta (), to designate wall-backfill interface friction angle and the Greek letter,Rho (), to designate the interface friction angle between geosynthetics and soil.3,43.2.4 Mohr-Coulomb shear strength envelope, nthe least squares, “best fit” straight line through a defined se
21、ction of the shearstrength-normal stress failure envelope described by the equation, = ca + n * tan ( ) (see 12.6). The envelope can be describedfor any chosen shear failure mode (example, peak or post-peak).3.2.5 secant friction angle, sec, n(angle of friction of a material or between two materials
22、, ) the angle defined by a line drawnfrom the origin to a data point on the shear strength-normal stress failure envelope. Intended to be used only for the normal stresson the shearing plane for which it is defined.3.2.6 shear strength, , nthe shear force on a given failure plane. In the direct shea
23、r test it is always stated in relation to thenormal stress acting 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.
24、2.6.2 post-peak shear strengththe minimum, or steady-state value of shear resistance that occurs after the peak shearstrength is experienced.3.2.6.3 DiscussionThe end user is cautioned that the reported value of post-peak shear strength (regardless how defined) is not necessarily the residualshear s
25、trength. In some instances, a post-peak shear strength may not be defined before the limit of horizontal displacement isreached.3.2.7 shear strength envelope, ncurvi-linear line on the shear stress-normal stress plot representing the combination of shearand normal stresses that define a selected she
26、ar failure mode (for example, peak and post-peak).4. Summary of Test Method4.1 The shear resistance between a geosynthetic and a soil, or other material selected by the user, is determined by placing thegeosynthetic and one or more contact surfaces, such as soil, within a direct shear box. A constan
27、t normal stress representative ofdesign stresses is applied to the specimen, and a tangential (shear) force is applied to the apparatus so that one section of the boxmoves in relation to the other section. The shear force is recorded as a function of the shear displacement of the moving sectionof th
28、e shear box.4.2 To define a Mohr-Coulomb shear strength envelope, it is recommended that a minimum of three test points be performedat different normal stresses, selected by the user, to model appropriate field conditions. However, there may be instances wherefewer test points are desired (see Note
29、1). The peak shear stresses, or shear stresses at some post-peak displacement, or both, areplotted against the applied normal stresses used for testing. The test data are generally represented by a best fit best-fit straight linethrough the peak strength values whose slope is the Mohr-Coulomb fricti
30、on angle for peak strength between the two materialswhere the shearing occurred. The y-intercepty-intercept of the straight line is the adhesion intercept. A straight line fit for shearstresses at some post-peak displacement is the post-peak interface strength between the two materials where the she
31、aring occurred.3 LRFD Bridge Design Specifications, 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, V
32、ol I, and FHWANHI-10-025, Vol II, U.S. Department of Transportation, Federal Highway Administration (FHWA), Washington, D.C., 2009.D5321/D5321M 172NOTE 1There may be some investigative cases where only a single test point is desired. If the field design conditions will experience a range ofnormal st
33、resses, it is standard industry practice to bracket the normal-stress normal stress range with tests on both sides of the range, as it is unconservativeto extrapolate results outside of the normal-stress normal stress range tested. When defining a Mohr-Coulomb shear strength envelope over a range of
34、normal stresses, standard industry practice is to use a minimum of three test points. Attempting to define a single linear Mohr-Coulomb shear strengthenvelope over too-large too large of a normal-stress normal stress range may prove to be problematic in many cases because most failure envelopes exhi
35、bitsignificant curvature over such a large range, particularly at low normal stresses on the shearing plane.5. Significance and Use5.1 The procedure described in this test method for determination of the shear resistance of the soil and geosynthetic orgeosynthetic and geosynthetic interface is inten
36、ded as a performance test to provide the user with a set of design values for thetest 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
37、, but caution is advised asoutlined in 5.2.1.5.2.1 The shear resistance can be expressed only in terms of actual test conditions (see Note 2 and Note 3). The determinedvalue may be a function of the applied normal stress, material characteristics (for example, of the geosynthetic), soil properties,s
38、ize of sample, moisture content, drainage conditions, displacement rate, magnitude of displacement, and other parameters.NOTE 2In the case of acceptance testing requiring the use of soil, the user must furnish the soil sample, soil parameters, and direct shear testparameters. The method of test data
39、 interpretation for purposes of acceptance should be mutually agreed to by the users of this test method.NOTE 3Testing under this test method should be performed by laboratories qualified in the direct shear testing of soils and meeting the requirementsof Practice D3740, especially since the test re
40、sults may depend on site-specific and test conditions.5.2.2 This test method measures the total resistance to shear between a geosynthetic and a supporting material (substratum) ora geosynthetic and an overlying material (superstratum). The total shear resistance may be a combination of sliding, rol
41、ling, andinterlocking of material components.5.2.3 This test method does not distinguish between individual mechanisms, which may be a function of the soil andgeosynthetic used, method of material placement and hydration, normal and shear stresses applied, means used to hold thegeosynthetic in place
42、, rate of shear displacement, and other factors. Every effort should be made to identify, as closely aspracticable, the sheared area and failure mode of the specimen. Care should be taken, including close visual inspection of thespecimen after testing, to ensure that the testing conditions are repre
43、sentative of those being investigated.5.2.4 Information on precision among laboratories is incomplete. In cases of dispute, comparative tests to determine whethera statistical bias exists among laboratories may be advisable.5.3 The test results can be used in the design of geosynthetic applications
44、including, but not limited to, the design of liners andcaps for landfills, mining heap leach pads, tailings impoundments, cutoffs for dams and other hydraulic barriers, geosynthetic-reinforced retaining walls, embankments, and base courses; in applications in which the geosynthetic is placed on a sl
45、ope; fordetermination of geosynthetic overlap requirements; or in other applications in which sliding may occur between soil and ageosynthetic or between two geosynthetic materials.5.4 The displacement at which peak strength and post-peak strength occurs and the shape of the shear stress versus shea
46、rdisplacement curve may differ considerably from one test device to another due to differences in specimen mounting, grippingsurfaces, and material preparation. The user of results from this test method is cautioned that results at a specified displacementmay not be reproducible across laboratories
47、and that the relative shear displacement measured in this test at peak strength may notmatch relative shear displacement at peak strength in a field condition.6. Apparatus6.1 Shear DeviceArigid device to hold the specimen securely and in such a manner that a uniform shear force without torquecan be
48、applied to the tested interface. The device consists of both a stationary and moving container, each of which is capable ofcontaining dry or wet soil and areis rigid enough to not distort during shearing of the specimen. The traveling container must beplaced on firm bearings and rack to ensure that
49、the movement of the container is only in a direction parallel to that of the appliedshear force.NOTE 4The position of one of the containers should be adjustable in the normal direction to compensate for vertical deformation of the substrate andgeosynthetic.6.1.1 Square or rectangular containers are recommended. They should have a minimum dimension that is the greatest of 300mm 12 in., 15 times 15 the d85 of the coarser soil used in the test, or a minimum of five times 5 the maximum opening size(in plan) of the geosynthetic tested. The
