Force transmission and anisotropic characteristics of sheared granular materials with rolling resistance

Abstract

We adopt a two-dimensional granular assembly in a direct shear box to systematically investigate the role of rolling resistance during the shearing process. A discrete element method with parallel computation and a rolling friction model is utilized in this paper. The macro- and microscale responses are sensitively subjected to a change in the rolling friction. The critical-state indices are found to be linearly related to each other, and the linear relationship between the critical-state indices and the rolling friction coefficient is evidently observed. The macro- and microscopic relationships are discussed from the connections between the stress and fabric properties. For microscale behaviors, different rolling frictions can generate various magnitudes of arching effects caused by antirotation and pose different characteristics to the force chains. The algorithm related to the extraction of force chains is adopted to explain the local sustaining structures. The localization, length, number and magnitude distribution of the force chains depend on the rolling friction. The influence of the rolling resistance on the friction mobilization is evident. A transition of the force distribution from the exponential to the Gaussian distribution is observed when the rolling resistance conditions change. The strong–weak contact systems and various anisotropic parameters are utilized to characterize the mechanical and geometrical roles of rolling resistance.