Standard Test Method for Torsional Ring Shear Test to Determine Drained Residual Shear Strength of Fine-Grained Soils

Importancia y uso:

5.1 The ring shear test is suited to the relatively rapid determination of drained residual shear strength because of the short drainage path through the thin specimen, the constant cross-sectional area of the shear surface during shear, unlimited rotational displacement in one direction, and the capability of testing one specimen under different effective normal stresses to obtain clay particles that are oriented parallel to the direction of shear to obtain residual shear strength envelope.

5.2 The apparatus allows a reconstituted specimen to be overconsolidated and presheared prior to drained shearing. Overconsolidation and preshearing of the reconstituted specimen significantly reduces the horizontal displacement required to reach a residual condition, and therefore, reduces soil extrusion, wall friction, and other problems (Stark and Eid, 1993)3. This simulates a preexisting shear surface along which the drained residual strength can be mobilized.

5.3 The ring shear test specimen is annular so the angular displacement differs from the inner edge to the outer edge. At the residual condition, the shear strength is constant across the specimen so the difference in shear stress between the inner and outer edges of the specimen is negligible.

Note 1: Notwithstanding the statements on precision and bias contained in this test method: The precision of this test method is dependent on the competence of the personnel performing it and the suitability of the equipment and facilities used. Agencies that meet the criteria of Practice D3740 are generally considered capable of competent testing. Users of this test method are cautioned that compliance with Practice D3740 does not ensure reliable testing. Reliable testing depends on several factors; Practice D3740 provides a means of evaluating some of those factors.

Subcomité:

D18.05

Referida por:

D7608-18E01

Volúmen:

04.09

Número ICS:

13.080.20 (Physical properties of soil)

Palabras clave:

consolidated; drained test conditions; multi-stage test; reconstituted specimens; residual shear strength; ring-shear test; single stage test; torsional ring shear test ;