SINGLE HARDENING CONSTITUTIVE MODEL FOR SOIL, ROCK AND CONCRETE

A constitutive model with a single yield surface has been developed for the behavior of frictional materials such as clay, sand, concrete, and rock. The model is based on concepts of elasticity and plasticity theories. In addition to Hooke's law for the elastic behavior, the framework for the plastic behavior consists of a failure criterion, a nonassociated flow rule, a single yield criterion that describes contours of equal plastic work, and a work-hardening/softening law. The functions that describe these components are all expressed in terms of stress invariants. The model incorporates twelve parameters for frictional materials with effective cohesion such as concrete and rock. These parameters can all be determined from simple experiments such as isotropic compression and triaxial compression tests. Examples of predictions of the behavior of sand in undrained triaxial compression and of concrete under three-dimensional loading conditions are presented.