The fracture and fragmentation of rock materials are basic and important problem in geomechanics and blasting engineering. An approach, which can simulate the process of fracture and fragmentation of rock materials, is introduced in this work. A beam-particle model is first introduced in the frame of the discrete element method. In the beam-particle model, the neighboring elements are connected by beams. Consequently, a beam network is formed in the particle system. The strength characteristics of rock materials are reflected by the beam network. The strength criterion was then built to verify whether a beam exists or not. The process of rock fracture and fragmentation is described by the gradual disappearance of beams. Finally, two cases were presented to indicate the validity of the method proposed in this work.

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The proportion of on-site mixed emulsion explosives in mining is getting higher and higher, in order to better use the explosive performance of mixed explosives to improve energy utilization. Based on the wave impedance theory, the wave impedance of mixed explosives is changed to make rocks The wave impedances are matched to achieve the purpose of improving the blasting effect and reducing the bulk rate. After field test, increasing the sensitizer content within a certain range is beneficial to the improvement of explosive performance. When the explosive sensitizer content is 1.15%, the best matching coefficient of mixed explosive and rock impedance is 2.51, the rock after blasting is large. The block rate is reduced and the rock crushing effect is better. After this matching test, it is shown that it is feasible to improve the blasting performance by adjusting the explosive performance of the explosive by the optimal wave impedance coefficient according to the hardness of the rock, which can provide reference for the peers.

Using the caustics method and the experimental system of digital laser dynamic caustics, the model experiment of drop hammer impact loading was carried out, and the effect of the defect shape (circular and rectangular) and the filling material (air, epoxy, and silicone rubber) on the propagation behavior of the running crack was investigated. The experimental results show that, under the impact loading, the running crack initiates at the end of precrack and propagates toward the defect. After the running crack connects to the defect, it accumulates energy within a certain period before initiating again at the upper edge of the defect. Subsequently, only one running crack is formed at the upper edge of the circular defect, but two running cracks are formed at the upper edge of the rectangular defect. The defect shape and the filling material have a significant effect not only on the energy accumulation time of the running crack at the defect but also on the stress intensity factor when initiating at the defect. The effect degree of the defect shape on the running crack propagation behavior is in the following order: circular defect > rectangular defect, whereas the effect degree of the filling material on the running crack propagation behavior follows this order: air > silicone rubber > epoxy.