Effect of microstructure on undrained behaviour of sands

This paper presents a mathematical modelling of the effects of initial fabr ic on the mechanical behaviour of sand. A stress-dilatancy model that incor porates microstructural aspects of sand is hereby obtained while writing en ergy conservation for an ensemble of particles over a representative elemen tary volume at micro- and macro-scales. The resulting stress-dilatancy mode l, when used within an elastoplastic framework, successfully reproduces cer tain aspects of sand behaviour that are reflective of its microstructure un der both drained and undrained conditions. The role of microstructure in re lation to the characterization of steady, quasi-steady, and phase-transform ation states is discussed within the framework of the model. Numerical simu lations obtained from the proposed model are generally very consistent with experimental observations and provide insightful information.