A new approach to anisotropic, bounding surface plasticity: general formulation and simulations of natural and reconstituted clay behaviour

It is demonstrated that an efficient framework for the description of a two surface kinematic hardening/bounding surface plasticity model can be devised if the model is conceived in a normalized stress space in which the bounding surface remains of constant size. The hardening of the bounding surface is contained in the transformation laws linking ‘real’ and ‘normalized’ stresses while the geometric rules controlling kinematic hardening are considered only in terms of normalized stresses. Within the general framework thus constructed, two particular models are developed in outline. Owing to the proposed anisotropic hardening, these models are shown to have the ability to reproduce the observed characteristics of the progressive destructuration of natural cemented clays and of the plastic anisotropy of reconstituted soils.