Evolution of Shear Modulus and Fabric During Shear Deformation

Abstract

Numerical studies of shear modulus and fabric for sphere assemblies were performed by a discrete element code, TRUBAL. Results of numerical experiments were compared with physical experiments. In general, numerical experiments simulate the stress-strain behavior and shear modulus of physical results quite well both qualitatively and quantitatively. Shear modulus has a close relationship with the coordination number. After a cycle of loading and unloading, there is an induced anisotropic fabric and are locked-in inter-particle shear forces which reflect the previous stress history. This is also reflected in a decrease in both the shear modulus and the coordination number. During reshear locked-in inter-particle shear forces would influence the behavior of shear modulus. When resheared in the previous direction inter-particle shear forces decrease first which results in an increase of shear modulus in the initial portion of loading. While resheared opposite to the previous direction initially high inter-particle shear forces would decrease the shear modulus.