ABSTRACT
Granular materials exhibit a complex mechanical behavior when they are loaded. This macromechanical response is a result of the discrete character of the media, and depends on the grains themselves (shape, angularity, size and so on), the evolution of the granular skeleton (void ratio, fabric), and some phenomena occurring at the grain scale (rolling, sliding). This global response also involves the existence of the so-called asymptotic stress-strain behaviors, which are a very important feature in granular soils. These asymptotic states are independent of the initial state of the material, and they have been used as fundamental principles for the formulation of several constitutive relations (Schofield & Wroth, 1968; Gudehus, 1997). By means of numerical simulations, it has been possible to study different phenomena occurring at the micro-mechanic scale (Cundall et al. 1979; Alonso-Marroquín & Herrmann, 2004), and to reproduce the global response observed in realistic experiments of granular materials (Peña et al. 2004).
