Dynamic Strength of Anisotropically Consolidated Sand

Analysis of the stability of an earth slope during an earthquake requires a knowledge of the strength of samples of soil which have been consolidated anisotropically to stresses equivalent to those acting in the ground behind the slope, and then subjected to pulsating stresses simulating those expected to act on soil elements during an earthquake. A large number of such tests were performed on laboratory samples of saturated sands and a compacted silt. The data indicated that the strength under pulsating loading increased with increasing density and increasing confining pressure. At low pressures the pulsating loading strength was significantly less than the strength under static loading conditions, while at high pressures the pulsating loading strength was slightly greater than the static undrained strength. The anisotropic consolidation stress conditions had a major influence on the pulsating loading strength; the higher the ratio of major to minor principal stress during consolidation, the higher was the strength under pulsating loading conditions.