The mechanical behaviour of a natural clay: Experimental results and constitutive modelling

Recent experimental results have demonstrated the influence of the initial soil structure and of the structural degradation that develops with straining on the mechanical behaviour of natural clays. The first part of this paper briefly examines the mechanical behaviour of an Italian natural stiff clay, the Pappadai clay, in order to outline the main effects of the natural soil structure and of its changes with straining on the clay behaviour. This is followed by the description of the simplified version of a recently developed constitutive model for natural clays, which can simulate the effects of the degradation of the initial structure on clay behaviour. The model is then used to simulate some of the experimental test results for natural Pappadai clay. The calibration procedure used to derive the values of the model parameters for the clay is presented and the numerical results are compared with the experimental data.