Test procedures for ring shear apparatus

Many factors influence the accuracy of the ring shear tests, and the test procedure is one of them. The Bromhead ring shear apparatus employs the top load plate for shear, and the gap between the load plate and the specimen container is set. It is observed in the experiment that the soil specimen is extruded with the increase of shearing displacement. The magnitude of the wall friction developed during shear is directly linked to the intrusion of the top plate into the specimen container. The actual shearing stress on the specimen is less than the measured stress. Three test procedures are discussed. Compared with the multistage ring shear test procedure, the single-stage test procedure can avoid more rotational displacement of the load plate, minish extrusion effect and decrease test error. The ring shear tests on sand sepecimens show that the residual strength of sand of the single-stage shear test procedure is less than that of multistage one.