科研之友
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摘要
The cave mining method relies on gravity to fragment the rock mass into blocks that can be extracted out of drawpoints. Several discrete element method (DEM) models on gravity flow are presented in the literature; however, only a few of those consider rock shape and secondary fragmentation. In this paper, the reliability of the particle flow code (PFC) to model gravity flow of fragmented rock is validated against known experimental results. A new method to create complex shape clusters is proposed and then used to investigate the mechanisms of gravity flow and the influence of particle bond strength on the secondary fragmentation, and the evolutions of the movement zone and extraction zone. The model results are validated against the upside-down drop shape theory for two cases: (1) constant size of fragmented rock blocks and (2) changing size due to breakage of the fragmented rock blocks. For the latter case, the results show that secondary fragmentation of weaker rocks would result in a wider movement zone and extraction zone than that of stronger rocks.
