Non-coaxiality and stress-dilatancy rule in granular materials: FE investigation within micro-polar hypoplasticity

This paper deals with FE investigations of shear localization in dilatant granular bodies. The calculations were carried out with a hypoplastic constitutive law enhanced by micro-polar terms to properly model the shear zone evolution. The behaviour of an initially medium dense sand specimen with very smooth and very rough horizontal boundaries was analyzed during a plane strain compression test. A stochastic distribution of the initial void ratio was assumed to be spatially correlated. Attention was focused on the non-coaxiality of the directions of the principal strain increments and principal stresses in the shear zone and on the stress-dilatancy rule. Copyright (C) 2008 John Wiley & Sons, Ltd.