Anisotropy in particle contacts associated with shearing in granular media

Summary Work on directional properties in granular media is briefly reviewed with an emphasis on the angular frequency of normals to particle contact tangents. Data from a two dimensional model material is compared with that of sand sheared in plane strain with a similar stress path. This stress path included a chosen sudden change in major principal stress direction.Directional stress-strain behaviour in granular media is related to the changing angular frequency of particle contacts. Measurements of this changing frequency are related to new model predictions and actual experimental data for sand sheared in plane strain.With 5 Figures