Abstract:
In view of the increasingly prominent risk of mining-induced seismicity during the westward shift of coal mining development in China, this paper systematically analyzes the distribution patterns, typological characteristics, and occurrence mechanisms of mining-induced seismicity in Chinese coal mines. Besides, the formation mechanism of mining-induced seismicity in long-wall working face dominated by hard-thick roof is examined, and the elastic wave attenuation coefficients of mining-induced seismicity for typical mines in the Ordos Basin is inverted. Finally, a key integrated technology for coordinated prevention and control via surface fracturing, which combines vertical well layered fracturing with horizontal well precision fracturing, is proposed and then validated through engineering practice. The results indicate that mining-induced seismicity in China exhibits significant spatial clustering, and the frequency of mining-induced seismicity is generally positively correlated with regional coal production. Furthermore, high-incidence areas correspond to regions of intensive coal mining activities, confirming that mining operations are the primary trigger. Additionally, based on mining methods and techniques, mining-induced seismicity can be categorized into two types: that induced by shortwall mining and that induced by longwall mining. The former is primarily triggered by the instability of coal pillars in goafs, while the latter mainly results from the delayed fracture of hard-thick roofs. In the deep long-wall working faces of the Ordos region, mining-induced seismicity is predominantly of the roof movement type. A roof load-bearing structure model was constructed, and a formula for calculating the energy released during roof fracture was derived. Consequently, the relationships among hard-thick roof fracture and rock tensile strength, roof fracture and stratum thickness, as well as stratum thickness and energy release were systematically elaborated. Notably, the average elastic wave attenuation coefficient (
α) for typical Ordos mines was determined to be
0.001, elucidating the mechanism behind mining-induced seismicity in long-wall working face dominated by hard-thick roof. A technical framework encompassing well-type optimization, layout design, and horizon identification was established. Engineering practice demonstrated that surface fracturing can achieve artificial pre-fracturing to weaken the roof, markedly reducing both the frequency and energy release of mining-induced seismicity and thereby enhancing the safe advance efficiency of working faces. Overall, this study provides theoretical support and an engineering paradigm for the safe and efficient prevention and control of mining-induced seismicity and rockburst in hard-thick roof mining areas of Western China.