Effects of end conditions on soil shear strength parameters during triaxial testing

Abstract

Review of literature suggests that in order to get a more uniform stress and strain distribution during triaxial test of soil, it is necessary to reduce the sample height/diameter ratio from 2 to 1 and to eliminate friction between the sample ends and the platens. The theoretical analysis has shown that the soil shear strength parameters within certain limits depend on the height/diameter ratio of the soil sample. The same has been proved by the experiments carried out. Therefore, the reduction of the sample height/diameter ratio till 1 is recommended for the clay samples, but not for sands. Eliminating friction between the sample ends and the platens, i.e. allowing the sample base freely to move horizontally, the shear stress on the sample end is eliminated. Thus, different residual values of shear strength for samples with regular ends and free horizontal movement were obtained. Therefore, the soil shear strength parameters achieved are also different.