Effects of Fabric Anisotropy of Sand on Cyclic Undrained Triaxial and Torsional Strengths

Abstract

ABSTRACT In order to examine the effects of fabric anisotropy on the relationships between the cyclic triaxial and torsional shear strengths, a series of cyclic undrained triaxial and torsional shear tests was performed on three kinds of sands made by three different sample preparation methods. The test results showed that the cyclic undrained strengths varied with sample preparation methods. In particular, the effects of sample preparation methods were clearly observed in the triaxial test. The relationships between the cyclic triaxial and torsional shear strengths also varied with sample preparation methods. In addition, it was found that the effects of fabric anisotropy due to the difference in the sample preparation methods appear in the axial deformation and the developed pore water pressure characteristics during the cyclic triaxial test. In order to evaluate quantitatively the effects of fabric anisotropy on the relationships between the cyclic triaxial and torsional strengths, new index parameters were introduced, which express the degree of the anisotropy of specimens. Consequently, it was indicated that there exists a unique rule between these parameters and the ratio of torsional strengths to triaxial strengths.