Unified hardening model for soils

Unified hardening(UH) model is an elastoplastic model system proposed based on the Cam-clay model, which includes two basic elements, namely, transformed stress method and unified hardening parameter. The model is combined with strength criteria by adopting the transformed stress methods on the basis of the SMP criterion, the Lade's criterion and the generalized nonlinear strength theory. The model, to which the unified hardening parameter is introduced, is able to describe many mechanical behaviors, including strain hardening and softening, stress dilatancy, over-consolidation, inherent anisotropy, structure, creep compression, asymptotic state and so on. Fewer parameters required in the model are determined by the conventional triaxial test. The model not only develops the Cam-clay model but also is easily exploited in the engineering software. Therefore, its application to engineering appears to be highly promising.