Constitutive modelling for granular media using an anisotropic distortional yield model

Summary It has been attempted here to model the mechanical response of granular media through a combination of analytical, numerical and experimental techniques. Based on the experimental evidence obtained from a series of triaxial laboratory experiments on specimens made of glass beads, the model attempts to simulate the movement of yield surfaces and the stress-strain relationships. It is found that the yield surface distorts in the direction of loading in a manner analogous to that of metals. An anisotropic distortional yield model is formulated in order to describe the experimental behavior exhibited by these granular media. From the experimental yield surfaces the parameters of the model have been evaluated and a hardening rule, based on the Phillips rule, has been determined. Associativity on the -plane has been observed experimentally. Using these concepts the constitutive formulation has been presented and the stress-strain curves have been generated. From the comparisons of these curves we observe a good correlation between the model and the experimental observations.