Measurement and correlations of K and V_s anisotropy of granular soils Available to Purchase

The coefficient of lateral earth pressure at rest (K₀) and stress-dependent shear wave velocity (V_s) of granular soils under one-dimensional compression loading were measured using a modified floating wall consolidometer-type bender element testing system. The V_s of the granular soils was monitored through paired bender elements installed in the floating wall and on top and base platens, and the V_s anisotropy of the soils was investigated by comparing the V_s values in three orthogonal directions. Granular materials such as glass beads (GB) and Ottawa sand with different shapes and sizes were adopted and the effects of particle shape and size and stress level on K₀ and V_s anisotropy were discussed. From the laboratory observations, K₀ was found to be dependent on the particle shape and surface roughness. The anisotropic stress state was found to play a major role in governing the V_s anisotropy of the GB; however, the V_s anisotropy of the sand resulted from the inherent geometry/fabric anisotropy and manifested by the anisotropic stress state. In addition, the degree of cross-anisotropy was defined and used to evaluate the cross-anisotropic properties of the geomaterials.