Constitutive model with a concept of plastic rebound for expansive soils

Abstract

This study examines the applicability of an elasto-plastic constitutive model with the concept of plastic rebound to describe the mechanical behaviour of expansive soils. The constitutive model can be characterized by an elliptical yield locus which is analogous to the modified Cam-clay model, but does not pass the origin of the effective stress space. In addition to the intrinsic normal consolidation line, the plastic rebound line is newly defined in order to describe a hardening law which allows the prediction of plastic swelling upon unloading. Through analytical investigations, the paper shows that the constitutive model can effectively predict not only the volume changes, but also the effective stress paths, i.e., K0-values, for both consolidation and swelling in axial and radial problems, despite it being a simple modification. Also presented here are comparisons between the results of a simulation and laboratory tests on expansive soils in order to verify the applicability of the developed constitutive model.