Abstract
Monotonic and cyclic shear tests are carried out to study volume change characteristics of gravelly sands. In monotomc tests, the relative density of gravelly sands corresponding the critical void ratio ecr decreases with the increase of uniformity coefficient Uc, indicating that positive dilatancy is more dominant for gravelly soils with larger Uc. On the other hand, volume reduction of gravelly sands under cyclic loading, which is almost independent of Uc, depends greatly on whether initial void ratio is larger than ecr determined in monotomc loading. An empirical equation for the volumetric strain of gravelly sands is proposed considering the effects of Dr, cyclic stress ratio and the number of cyclic loading.
