Influence of contact friction on macro-micro mechanical behavior and energy evolution of granular materials

The friction characteristics of geotechnical granular materials are closely related to the roughness of the particle surface and the particle shape. The roughness surface will hinder the relative sliding between particles while the irregular particle shape will hinder the rolling between particles. The conventional triaxial tests with different values of the sliding friction coefficientμrand the rolling friction coefficientμrwere carried out to study the influence of the inter-particle contact friction on the macro and micro mechanical properties and energy evolution of granular materials by using linear-based rolling resistance model in discrete element method(DEM). The results show that for the materials with similar particle shape(the sameμr), the dilatancy and the peak strength increase with increasing the particle roughness, while the residual strength changes little. For the granular materials with smooth surfaces, the irregularity of the particle shape has little effect on the peak and residual strengths. For the coarse granular materials, however, the irregularity of the particle shape can obviously improve the peak and residual strengths. From the microscopic perspective, the influence of the surface roughness and the particle shape on the proportions of sliding and rolling contacts, as well as the evolution of the micro energy, were analyzed during shearing. © 2022, Science Press. All right reserved.