ABSTRACT
ABSTRACT: The incremental behavior of granular materials is characterized by strong nonlinearity. Accurate experimental investigations of the incremental response are therefore needed to define a proper constitutive model. In substitution of experiments, the incremental behavior of granular soils can be investigated by numerically simulating stress probing experiments on a 3D Distinct Element model consisting of a random assembly of spheres. Calvetti et al. (2002, 2003a) discussed the reliability of a 3D Distinct Element model as a substitute for real granular materials by reproducing experimental results presented by Royis and Doanh (1998), and extensively studied its incremental behavior under axisymmetric and deviatoric probing conditions. Following the work presented by Calvetti et al. (2003b), which was restricted to axisymmetric probing, this paper presents a micro mechanics interpretation of the results obtained upon deviatoric stress probing. In particular, micro-macro relationships are proposed between the activation of contact sliding and the occurrence of plastic strains at the macroscopic scale. Both responses from a preloaded and a virgin initial state are discussed.
