EXPERIMENTAL STUDY OF ANISOTROPIC SHEAR STRENGTH OF SAND BY PLANE STRAIN TEST

Abstract

Anisotropic parallel alignment of particles is universally observed not only in river, beach and coastal dune sands but also in artificially deposited sands. Anisotropic shear strength caused by the anisotropic parallel alignment of particles can be observed more clearly in the plane strain condition ε₂=0 than in the symmetrical stress condition σ₂=σ₃. This must be chiefly due to the fact that re-arrangement of particles during shear deformation can be more easily performed in the latter condition than in the former one. Shear strength of sand in a plane strain test has been generally believed to be 10% to 20% greater than that obtained in a triaxial compression test. When the specimen is compressed at a small angle to a bedding plane, however, it is possible that the shear strength in the plane strain test is smaller than that in the triaxial compression test. The effect of anisotropic shear strength cannot be ignored when stability problems and earth pressure problems in plane strain condition are analyzed.