On the elasticity and plasticity of dilatant granular materials

We present a model which simulates the response of a granular material (mad e up of nonplastic grains) to small cyclic shear strain. The model is based upon a dissipation function representing energy dissipated as plastic defo rmation and a quadratic dilatancy rule describing the volume response which produces kinematic hardening. Elastic deformation is included in the model through a function describing the rate at which it is stored as deformatio n occurs. Two sets of experimental data (one for a shear test, the other fo r a circular loading test) are used to evaluate the accuracy of the model. For the shear test, both the shear strain-shear stress curve and the shear strain-volume strain curve are reproduced well. In the circular loading tes t, the principal strain response and volume response are modelled realistic ally. (C) 1999 Elsevier Science Ltd. All rights reserved.