Modeling stress-dilatancy for sand under compression and extension loading conditions

Experimental results show very different stress-dilatancy behavior for sand under compression and extension loading conditions. In order to describe the behavior in both compression and extension conditions, two separate dilatancy equations are needed; one for each case. Furthermore, the effect of inherent anisotropy has not been considered in those equations. In this paper, a new micromechanics based method is presented, by which the stress dilatancy relation is obtained by considering the slip mechanism of the interparticle contacts in all orientations. The method also accounts for the effect of inherent anisotropy in sand. Experimental results on Hostun sand and LSI-30 sand are used for illustration the proposed method. © 2010 ASCE.