ABSTRACT
B.LORET Laboratoire de Mécanique des Solides, École Polytechnique, Palaiseau,
France
1 INTRODUCTION
Modelling the behaviour of geomaterials under various stress-paths can be achieved through the introduction of multiple sources of plasticity. Roughly speaking, the idea is to reproduce at the level of a sample the intracrystalline slips observed in crystals. This is however only a formal analogy because the sources of plasticity are difficult to define (Section 2). Applications of the general ideas presented hereafter can be found in the models by Lade11 and Vermeer.23 As a first step, the reader is introduced to the notions of activation and dependence of plasticity mechanisms; these points do not seem to have been considered with sufficient care in applications to geomechanics (Section 1).
