Research Progress on Microwave-Assisted Rock Fragmentation Technology: Multi-Field Coupling Mechanisms, Multi-Scale Damage Characterization, and Frontier Engineering Applications

As a disruptive technology to overcome the bottlenecks of conventional mechanical excavation and blasting, microwave-assisted rock fragmentation demonstrates tremendous potential in deep geo-resource development and extreme-environment engineering. This paper presents a comprehensive review of the latest advances in this field, thoroughly dissecting the electromagnetic–thermal–mechanical–chemical (THMC) multi-field coupling mechanisms governing microwave–rock interactions. Particular emphasis is placed on elucidating the mechanisms of thermal stress fracturing, phase-transition expansion, and thermo-chemical coupling damage triggered by mineral dielectric heterogeneity. The nonlinear effects of microwave radiation parameters, intrinsic rock properties, and complex in-situ stress environments on fracturing efficiency are rigorously analyzed, and precision multi-scale characterization methodologies—from macroscopic mechanical degradation to microscopic fracture networks—are comprehensively summarized. Building upon this foundation, the paper critically evaluates the current engineering application status and electromagnetic safety shielding challenges of this technology in frontier scenarios, including microwave-assisted tunnel boring machines (TBM), intelligent mineral sorting, deep unconventional oil and gas fracturing, and space in-situ resource utilization (ISRU). Finally, the limitations of existing research regarding cross-scale effects, high-temperature and high-pressure in-situ testing, and dynamic intelligent control are identified, and future development pathways oriented toward multi-source data fusion and adaptive power modulation are prospected, aiming to provide robust theoretical support and forward-looking guidance for the cross-scale engineering transformation of microwave rock-breaking technology.