ON THE BREAKAGE PATTERN OF PARTICLE BEDS UNDER CONFINED COMPRESSION:TEST AND NUMERICAL STUDY

Rock avalanche is characterized by complex kinematic process where drastic deformation and frequent collision with surrounding mountains of high-speed sliding rock mass may contribute to further dynamic fragmentation and progressive breakage of internal clastic rock fragments. It is of great significance to investigate the underlying mechanism of progressive breakage of rock fragments and its effects on macro deformation and mechanical behavior of sliding rock mass. This paper aims at the study of the progressive breakage failure of particle beds. Firstly, a series of confined compression tests were conducted on a type of spherical ceramic particle chosen to simulate quasi-brittle rock materials, and the comminution patterns and the mechanism behind were analyzed. Secondly, a three-dimensional numerical model was established which is capable of incorporating random deposition of spherical particles of prescribed size distribution and the frictional contact interaction between adjacent particles. The potential damage and fracture within a particle was simulated by a continuum damage material model. The test results demonstrate that tension splitting fracture dominates the size reduction performance of spherical particles under confined compression, and the variation of size distribution of the feed can mobilize different comminution patterns. The numerical results of particle breakage pattern compare favorably with the test results, and the numerical model can be extended for future applications in the progressive damage and disintegration behavior of particle assemblies made up of irregular rock fragments.