A CONSTITUTIVE MODEL COUPLING ELASTOPLASTICITY AND DAMAGE FOR COHESIVE-FRICTIONAL MATERIALS

In order to model the various phenomena which govern the mechanical re sponse of bonded geomaterials under monotonic loadings, an elastoplast ic model coupled with an elastic model with damage was developed, taki ng into account both the frictional and cohesive aspects of these mate rials. First, the principles at the base of the model are presented, a s well as the physical meaning of the parameters which were used in th e elastic model with damage. In order to illustrate the capabilities o f the model to reproduce the mechanical behaviour of bonded geomateria ls, we simulated triaxial tests on various materials: a deep cemented clay, whose heterogeneity from one specimen to another appeared mainly due to the calcium carbonate content; an assembly of sintered glass b alls; and an artificially cemented sand. In this last example, various initial mean stresses allowed us to enlighten the brittle-ductile tra nsition which was modelled by introducing the mean confining pressure in the damage evolution law. We demonstrated that the parameters of ea ch part of the model could be adapted to reproduce the observed genera l trends. For weak bonds, the elastoplastic part played the predominan t role, whereas for strong bonds, the elastic part with damage governe d the mechanical behaviour. (C) 1998 John Wiley & Sons, Ltd.