Abstract: In order to simulate the physic-mechanical properties of soil-rock mixture (SRM) realistically, a technique based on sphericity and angularity to constructing random geometric and discrete element method (DEM) model of irregularly shaped (IRS) rock block is proposed. Then particle flow simulations for open bottom cylinder tests of IRS rock blocks under different sphericity and angularity parameters are conducted. Finally, three dimensional (3-D) stochastic models of SRM which conform to the macroscopic statistical rule are established and DEM numerical simulations of large scale triaxial test are conducted. The numerical results and laboratory results are compared and analyzed. It is noteworthy that the proposed modeling method is simple and practical. The modeling controlling parameters are reasonable and effective. It is also indicated that particle flow simulation of SRM with stochastic IRS rock blocks can reproduce the physical and mechanical properties of SRM well, including mesoscopic contacting characteristics of IRS particles, stress-strain relationship, negative dilatancy and positive dilatancy. The proposed method in this paper provides an effective way to further study the deformation and failure mechanism of SRM.

Key words: soil-rock mixture (SRM), irregularly shaped (IRS) particles, 3D-DEM, open bottom cylinder test, large scale triaxial test