ASTM D5321/D5321M-20

5.1 The procedure described in this test method for determination of the shear resistance of the soil and geosynthetic or geosynthetic and geosynthetic interface is intended as a performance test to provide the user with a set of 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 in 5.2.1.

5.3 The test results can be used in the design of geosynthetic applications including, but not limited to: the design of liners and caps 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 slope; for determination of geosynthetic overlap requirements; or in other applications in which sliding may occur between soil and a geosynthetic 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 shear displacement curve may differ considerably from one test device to another due to differences in specimen mounting, gripping surfaces, and material preparation. The user of results from this test method is cautioned that results at a specified displacement may not be reproducible across laboratories and that the relative shear displacement measured in this test at peak strength may not match relative shear displacement at peak strength in a field condition.

1.1 This test method covers a procedure for determining the shear resistance of a geosynthetic against soil, or a geosynthetic against another geosynthetic, under a constant rate of deformation.

1.2 The test method is applicable for all 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 due to the nonuniform 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 each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in nonconformance with the standard.

1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.