Macroscale Yield Criteria for Geomaterials

This paper deals with the formulation of yield criteria for geomaterials. Three kinds of approaches will be described: the first is called coupled because it gives rise to the natural coupling between the meridian and the deviatoric sections of the resulting yield surfaces; the second is called uncoupled because it is based on the definition of two distinct functions, one meridian and one deviatoric; the third is called hybrid and can be seen as intermediate between the coupled and the uncoupled approaches. The analysis is restricted to isotropic criteria. True triaxial tests obtained from numerical specimen are then used to validate the approaches.