Research on the method of hard rock cracking based on microwave heating technology

The fracture of hard rock has always been the focus of geotechnical engineering.Due to the high hardness and strength of hard rock, severe tool wear and high energy consumption in the process of mechanical rock fracture(TBM tunneling and ore comminution) have always been the main problems restricting its application in hard rock.If the initial cracking of hard rock can be realized using some rational technologies and the physical mechanical parameters of hard rock can be effectively improved, it will provide a prerequisite for the wide application of mechanical rock fracture technology in hard rock.However, the current methods that assist rock fracture have some shortcomings such as small rock crashing volume.As one of the auxiliary rock fracture methods, microwave irradiation technology can realize the initial rock crashing.Based on the phenomenon of rock cracking under microwave irradiation, this study first analyzes the internal mechanism of microwave irradiation, microwave-assisted surrounding rock pre-cracked and microwave-assisted ore comminution at home and abroad, and then puts forward the improvements of microwave-assisted rock fracture.Finally, based on the microwave heating test of common high hardness materials-granite and magnetite ore, in terms of the fracture characteristics of microwave heating on granite, the priority order of the influence of rock confining pressure and microwave heating path on the strength of granite is studied, and the combination of “hydraulic fracturing + microwave irradiation” is proposed to fracture the granite under the constraint of lateral confining pressure in deep underground.In terms of the effect of microwave heating on ore crushing, the mechanical properties of layered magnetite ore and non-layered ore under different microwave heating methods and the potential value of microwave cooling path on improving the degree of ore crushing are investigated.The research results provide reference for the further application of microwave heating technology in the field of hard rock fracture.