Sample preparation of dense granular materials. Influence of void ratio e and coordination number Z* on the mechanical behaviour at failure

Abstract

This presentation includes a numerical technique to prepare dense 2D disc samples with loose contact network using DEM under periodic boundary conditions. We mainly focus on a numerical procedure to control void ratio (e) and coordination number (Z*) for two kinds of samples. It has been achieved by using various interparticle friction coefficient values during isotropic compression and shearing. One dense and one loose sample has been prepared by varying the preparation procedure. For the loose sample we control interparticle friction coefficient values to control density while for the dense sample we add an extra step of dilation thus controlling void ratio and coordination number quasi-independently. As a result of this difference in preparation the dense sample macroscopic angle of friction under shearing has been dictated by its initial void ratio instead of coordination number.