Morphology Characteristics of the Fragments Produced by Rock Grain Crushing

The morphology of fragments produced by grain fragmentation is a cause for great concern in many areas such as rockfill dam and the mining industry. Therefore, there is a need to conduct a quantitative analysis of the morphology characteristics of fragments produced by rock grain crushing. So far, few studies have focused on the qualitative analysis of fragment morphology, and quantitative studies are rare. This study presents a quantitative investigation of the morphology characteristics of fragments produced by the crushing of two groups of rounded and angular rock grains. The intact grain morphology is acquired using a 3D scanner, and the grain fracture and fragmentation are simulated using the combined finite-discrete element method (FDEM). The mesh refinement study indicates that a finite-element mesh size that leads to the fracture process zone to be discretized into at least five or six elements is used to eliminate or minimize the mesh size effect. Regular and spherical grains tend to get smaller largest fragments and larger second-largest fragments compared with grains with lower sphericity and convexity because of different fracture modes. Small differences have been observed in the distributions of fragment shape descriptors for grains in two groups. However, no monotonic relationship has been found between the distribution of shape descriptors and the fragment size, except sphericity. The distributions of sphericity for different size groups clearly suggest that larger-sized fragments tend to be more angular, which is consistent with the existing results.