Elasto-Viscoplastic Constitutive Equations for Clay and Its Application to Consolidation Analysis

The mathematical structure of Adachi and Oka’s model, a typical overstress type elasto-viscoplastic constitutive model, for normally consolidated clays is discussed. Since it has been recognized that the overstress type models cannot describe the acceleration creep and creep rupture, the Adachi and Oka’s model was modified so that it can explain the creep rupture including acceleration creep of normally consolidated clays. In addition, based on the Adachi and Oka’s constitutive model and Biot’s consolidation theory, one-dimensional consolidation problems were analyzed numerically by the finite element method. Results show that the proposed method can describe the effect of sample thickness and aging on consolidation phenomena.