Modeling of non-contact rock breaking process and analysis of rock destruction mechanisms for basalt under microwave treatment

The utilization of microwave technology for rock fragmentation is increasingly common in mining and geotechnical engineering. The Microwave-Direct Rock Destruction (MDRD) method applies microwave energy directly to melt rock strata, creating cavities that mitigate economic losses associated with tool wear. To elucidate the MDRD process and its heating dynamics, a comprehensive multi-physics fields model was developed, integrating the transmission of the microwave field, non-isothermal flow, and phase changes. Specifically, in the MDRD of basalt, the rock's microwave energy absorption is primarily influenced by changes in the electrical properties of materials during phase transitions. This absorption significantly shapes the temperature distribution within the rock, characterized by a gradual increase, followed by a rapid rise and eventual stabilization. Moreover, the growth and expansion of a molten core during the microwave heating process critically affect the depth of the resultant melting cavity. The developed model and its findings enhance the understanding of the MDRD process and offer valuable guidance for employing microwave technology in non-contact rock fragmentation methods.