Strain Space Multiple Mechanism Model for Clay Under Monotonic and Cyclic Loads

Abstract

The strain space multiple mechanism model, originally developed for cyclic behavior of granular materials such as sand, is adapted for idealizing stress strain behavior of clay under monotonic and cyclic loads. The proposed model has advantages over the conventional elasto-plastic models of Cam-clay type in the facts that (1) arbitrary initial K0 state can be analyzed by static gravity analysis, (2) stress induced anisotropy (i.e. effect of initial shear) in the steady (critical) state can be analyzed based on Shibata’s dilatancy model (1963), (3) over-consolidated clay can be analyzed by defining the dilatancy at the steady state based on over-consolidation ratio, (4) strain rate effects for monotonic and cyclic shear can be analyzed based on Isotach/TESRA models proposed by Tatsuoka et al (2002) in the strain rate ranging from zero to infinity in addition to the conventional strain rate effects of secondary consolidation (creep) type. Performance of the proposed model is demonstrated through simulation of drained/undrained behavior of clay under monotonic and cyclic loading.