A Stress-Dilatancy Relationship for Rockfill Incorporating Particle Breakage and Intermediate Principal-Stress Ratio

Rockfill material is widely used for construction of high rockfill dam, which undergoes significant particle breakage and three-dimensional stress path induced by the water pressure, earthquake, etc. The dilatancy equation, defined as the function of the dilatancy dg and the stress ratio η, is regarded as the foundation of elastoplastic constitutive model. Therefore, a dilatancy equation considering the influence of particle breakage and intermediate principal stress ratio b was proposed in this paper. A series of test data from rockfill materials including conventional triaxial test, constant-b test and plane strain test were used to verified the applicability of the equation. It was found that the proposed dilatancy equation considering two important factors (i.e., particle breakage and b-value) agree well with the rearranged test data of the rockfill material in terms of dg-η. While the other dilatancy equations showed significant poorer predictions when ignoring one or two of the factors. That is, the proposed dilatancy equation can well describe the dilatancy behavior of rockfill material when considering the combined influences of the particle breakage and b-value.