A SIMPLE CONSTITUTIVE MODEL FOR GRANULAR SOILS - MODIFIED STRESS-DILATANCY APPROACH

The dependencies of granular soil behaviour on void ratio and stress a re modelled within plasticity theory enriched by a modified stress-dil atancy law. Simplicity has been kept in the development of the constit utive law for easy future implementation in a finite element code. By using a void ratio dependent factor which measures the deviation of th e current void ratio from the critical one, Rowe's stress dilatancy eq uation is modified This modification indeed corresponds to a new energ y dissipation equation for a granular assembly which sustains kinemati cal constraints under the action of stresses. The proposed constitutiv e law predicts in a very consistent manner the response of sands in mo notonic loading conditions,for a large range of initial void ratios an d confining pressures without the need to make any adjustments to the material parameters. Well known published data for the drained triaxia l compression of Sacramento River sand was successfully modelled. (C) 1998 Elsevier Science Ltd. All rights reserved.