Static Shear and Liquefaction Potential

Abstract

The authors have made a valuable contribution to resolving some of the conflicting views on the influence of initial static shear stress on the behavior of sand subjected to cyclic shear under constant volume conditions. The writers admit that the simple shear test apparatus used by the authors is quite suitable for carrying out the constant volume cyclic loading tests. The ability of the apparatus to apply large shear strains at large shear stress ratios may be attributed to the fact that displacements rather than stresses are prescribed along the boundary surfaces of the specimen. In other words, the specimen is forced to deform into a parallelepiped with a well-defined average shear strain, at the expense of nonuniform stresses along the boundaries. On the other hand, the ring torsion shear apparatus developed by the first writer and Oh-Oka (8,10) was designed to reduce the nonuniformity in boundary shear stresses by making the specimen endless in the direction of shear and by making the height of the specimen proportional to the radius. As the authors point out, the ring torsion apparatus does impose nonuniform stresses and strains during consolidation. The first writer and Oh-Oka have shown, however, that such nonuniformity was considered insignificant. (Author)