A constitutive framework for the elastoplastic modelling of geomaterials

The object of this paper is the definition of a generalised constitutive model for geomaterials, based onelastoplasticity. Two are the tasks of the paper: the substantial enhancement of an existing hierarchicalyield function and the definition of an isotropic hardening constitutive model for the behaviour of bothcohesive and frictional geomaterials. After its definition, the new function will be compared with differ-ent yield surfaces existing in literature in both the deviatoric and the meridian representation. Thereafter,the constitutive model will be outlined by defining hierarchical expressions for hardening laws andstress–dilatancy relationship in order to take into account several aspects of soil behaviour. Finally, somecomparisons between data from experimental tests on clay and sand will be made to highlight thehierarchical structure of the proposed model.