ISO DIS 17892-10

Description / Abstract: This International standard specifies two laboratory test methods for the determination of effective shear strength parameters for soils under consolidated drained conditions using either a shear box or ring shear device. The shearbox test is generally used for the determination of peak effective shear strength parameters. The ring shear test is generally used for the determination of residual effective shear strength parameters of fine grained soils.

Residual effective shear strength parameters may also be obtained from shear box tests and peak effective shear strength parameters may also be obtained from ring shear tests.

This standard is applicable to the laboratory determination of effective shear strength parameters for soils in direct shear within the scope of geotechnical investigations.

The test method consists of placing the test specimen in the direct shear device, applying a pre-determined normal stress, providing for draining (and wetting if required) of the test specimen, consolidating the specimen under normal stress and then shearing the specimen. This shearing is imposed by displacing one part horizontally, relatively with respect to the other part of the specimen at a constant rate of shear-deformation. The shearing force and the horizontal and vertical displacements are measured as the specimen is sheared. Shearing is applied slowly enough to allow excess pore pressures to dissipate by drainage so that effective stresses are equal to total stresses.

The tests included in this standard are for undisturbed, remoulded, re-compacted or reconstituted soils. The procedure describes the requirements of a determination of the shear resistance of a specimen under a single normal stress. Generally three or more similar specimens from one soil are prepared for shearing under three different normal pressures to allow the shear strength parameters to be determined.

Special procedures for preparation and testing the specimen, such as staged loading and pre-shearing or for interface tests between soils and other materials, are not covered in this standard procedure.

NOTE 1 This document fulfils the requirements of the determination of the drained shear strength of soils in direct shear for geotechnical investigation and testing in accordance with EN 1997-1 and EN 1997-2.