Yield and cyclic behaviour of a strain space multiple mechanism model for granular materials

This paper reviews fundamental behaviour of a strain space multiple mechanism model for granular materials. Although this model has previously been implemented in a finite element program and used in the analysis of numerous practical problems for evaluating seismic performance of geotechnical works, most of the application was limited to the two dimensional boundary value problems. This paper reviews the theoretical link between the micromechanical and macroscopic behaviour of granular materials and discusses the relationship between the two and three dimensional behaviour of the model. The strain space multiple mechanism model characterizes a twofold structure of an assemblage of particles: the first is a multitude of virtual two dimensional mechanisms, the second a multitude of virtual simple shear mechanisms of one dimensional nature. Due to the twofold structure, a yield criterion specified in the micromechanical level does not reproduce the same yield criterion at the macroscopic level. There is an effect of the intermediate principal stress. Based on this finding, the paper proposes a methodology to introduce various macroscopic yield criteria, including Tresca, von Mises, extended Tresca, Drucker-Prager, Mohr-Coulomb, and extended Mohr-Coulomb criteria within the framework of the strain space multiple mechanism model. Performance of this model incorporating various yield criteria is demonstrated for monotonic and cyclic loading, under drained and undrained conditions. Copyright (c) 2005 John Wiley & Sons, Ltd.