Fabric evolution in a numerical direct shear test

This paper presents a three-dimensional discrete element study on the mechanical behaviour and fabric changes of elongated particle assemblages in a direct shear test. Assemblages with elongated particles are prepared under different preparation methods: random placing and deposition. Particles are generated inside a direct shear box with arbitrary orientations in the random placing method. In the deposition approach, two directions of deposition are used: perpendicular and parallel to the shear direction. Assemblages formed by different methods give significantly different initial particle orientations. Different dilatancy responses and shear strengths are resulted upon shearing. Change in fabric along the shear plane is noticeable and the magnitude of such rotation depends highly on the initial particle orientation.