1.1 This test method covers the determination of the consolidated drained residual shear strength of a soil material in direct shear. The test is performed by deforming a specimen at a controlled strain rate on or near a single shear plane determined by the configuration of the apparatus. The objective of the test is to shear the specimen in a forward and backward direction until a minimum or residual shear strength is determined. After large shear deformation an increase in the parallel orientation of soil particles in the direction of shearing occur, and a surface or a thin zone of remolded material is formed. Generally, three or more specimens are tested; each under a different normal load, to determine the effect normal load has on shear resistance. 1.2 Shear stresses and displacements are not uniformly distributed within the specimen. An appropriate height cannot be defined for calculation of shear strains. Therefore, stress-strain relationships or any associated quantity, such as modulus, cannot be determined from this test. 1.3 The determination of strength envelopes and the development of criteria to interpret and evaluate test results are left to the engineer or office requesting the test. 1.4 The results of the test may be affected by the presence of soil or rock particles or both (see Section 7). 1.5 Test conditions including normal stress and moisture environment are selected, which represent the field conditions being investigated. The rate of shearing should be slow enough to ensure drained conditions. 1.6 The values stated in inch-pound units are to be regarded as the standard. Within this test method, the SI units are shown in parentheses. The values stated in each system are not exact equivalents; therefore, each system must be used independently. 1.7 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 and health practices and to determine the applicability of regulatory limitations prior to use.
Repeated; Direct; Shear; Strength
The title and scope are in draft form and are under development within this ASTM Committee.
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