Experimental study on the determination method of pressure relief gas transportation and storage channel under multiple factors

In the increasingly intense high-intensity mining process of coal mines, many factors comprehensively influence the spatial distribution characteristics of overburden fissure. The characteristics of overburden fissure distribution have important guiding significance for gas control in mining. Explored the distribution characteristics of overburden fissure networks and the boundary characteristics of gas channels under multi-factor mining conditions (mining height, advancing speed, coal seam dip angle) through conducting two-dimensional physical similarity simulation experiments. Simultaneously analysed the changing trends of the development of "two longitudinal zones" and "five horizontal zones" of overburden fissures and their influencing factors and determined the boundary characterization parameters of gas storage and migration channels based on the comprehensive criteria of "Hf," "S," and "ρ". And evaluated the determination process of gas channels, established, and optimized the theoretical model considering multi-factor mining conditions. The results indicate that gas storage and migration channels mainly develop in the fracture migration zone. The range of development continuously increases with mining height and dip angle and decreases gradually as the working face advance speed increases. It elucidated the temporal variations of gas channels and provides theoretical support for optimizing the layout parameters of gas extraction boreholes and improving gas extraction efficiency.