Numerical Study on the Mechanical Behavior of Surrounding Rock in Deep Coal Seams under Fluidization Mining

Deep resource extraction holds significant economic, technological, and strategic importance, yet it is hindered by extreme challenges such as high in situ stress, complex rock mechanics, and heightened safety risks. Conventional mining techniques are proving to be increasingly inadequate under these conditions, thereby necessitating a paradigm shift toward fluidization mining. It is an innovative approach that eliminates the need for underground personnel and conventional roadways. In this study, the energy-transfer mechanisms and rock behavior under fluidization mining conditions were systematically examined through numerical simulations. Four mining schemes were comparatively analyzed: square inside-out, square outside-in, round inside-out, and traditional longwall mining. The simulation results reveal that fluidization mining significantly modifies the stress distribution, energy accumulation, and overlying stratum deformation relative to conventional mining approaches. Among the evaluated schemes, the round inside-out fluidization mining method demonstrated the most uniform stress distribution, lower energy concentration, and reduced rockburst risk, indicating superior performance in terms of both the safety and efficiency. These findings provide theoretical and technical insights supporting the implementation of fluidization mining in deep coal seams and provide a scientific basis for the prevention and control of dynamic disasters, particularly rockbursts.