ABSTRACT
Micro-macro relationships are of outmost importance to simulate the behavior of granular soils under various conditions efficiently. Indeed, depending on their density and on the mean pressure, sands may, for example, exhibit both contractive or dilative plastic deformations (Verdugo & Ishihara 1996). There is a second influence of the fabric of the material, constituted by the anisotropic distribution of the contact directions between sand grains: physical experiments on rolled cylinders (Calvetti, Combe, & Lanier 1997) or DEM numerical ones, e.g. (Luding 2004), showed different responses depending on the contact directions within the sample. Since the fabric is affected by loadings, conforming the direction of the principal major stress (Biarez & Wiendick 1963, Oda, NematNasser, & Konishi 1985, Calvetti, Combe, & Lanier 1997), sand samples with the same void ratio and mean pressures may show different contractive or dilative characteristics (Shahnazari & Towhata 2002, Doanh, Finge, & Boucq 2010).
