Strength anisotropy and shear band direction in plane strain tests of sand

Strength anisotropy and shear band direction at failure and their relationship for sands were studied experimentally. Using reconstituted specimens of air-pluviated Toyoura sand, plane strain compression (PSC) tests, torsional shear tests and a bearing capacity test with a strip surface footing were performed. Also PSC tests were performed using undisturbed specimens of sand taken from layers in the field, formed by secondary deposition under water. For both types of sands, a significant degree of strength anisotropy was observed. The paper discusses also the point that many of the apparent contradictions concerning the shear band direction reported in the literature may be explained, at least partly, by taking into account the relative direction of bedding plane in each case.