A NEW INCREMENTALLY NON-LINEAR CONSTITUTIVE LAW FOR FINITE-ELEMENT APPLICATIONS IN GEOMECHANICS

The authors present in the first part of this paper, a new incrementally non linear constitutive model for non-viscous materials. This model allows for avoiding constitutive iterations, in the case where the loading path is purely defined in terms of a strain history. This situation is always encountered in the finite element analyses using the displacement approach. This model is obtained by a generalization of the soil-structure interface laws (Boulon and al [5], Boulon [4]), using a three-dimensional rheological interpolation and a part of the formulations proposed by Darve [11]. An other advantage of this model is its ability to incorporate an unlimited number of identification paths. The detail of this constitutive model is exposed by Alachaher[1]. The second part of the paper shows an identification and a validation of this new model for global loading paths. The performances of this model have been shown for several loading paths on sand like undrained, oedometric and isotropic paths. These tests seems to be very favourable to the passage to finite element applications.