Testing and Micromechanical Modelling of Rockfill Materials Considering the Effect of Stress Path

We have extended the micromechanics-based analytical (M-A) model to make it capable of simulating Nuozhadu rockfill material (NRFM) under different stress paths. Two types of drained triaxial tests on NRFM were conducted, namely, the stress paths of constant stress ratio (CSR) and the complex stress paths with transitional features. The model was improved by considering the interparticle parameter variation with the unloading-reloading cycles and the effect of the stress transition path. The evolution of local dilatancy at interparticle planes due to an externally applied load is also discussed. Compared with Duncan-Chang’s E-u and E-B models, the improved model could not only better describe the deformation properties of NRFM under the stress path loading, but also present the volumetric strain changing from dilatancy to contractancy with increasing transitional confining pressures. All simulations have demonstrated that the proposed M-A model is capable of modelling the mechanical behaviour of NRFM in the dam.