Single‐Hardening Model with Application to NC Clay

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 from 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 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 eleven parameters for normally consolidated clay that can be determined from simple experiments, such as isotropic compression and consolidated‐undrained triaxial compression tests. A study of the three‐dimensional behavior of remolded, normally consolidated clay has served as a basis for evaluating the capabilities of the model. Overall acceptable predictions are produced for the normally consolidated clay.