School of Mining Engineering, Anhui University of Science & Technology
Engineering Laboratory for Safe and Precise Coal Mining of Anhui Province, Anhui University of Science &Technology
Key Laboratory of Safe and Effective Coal MiningMinistry of Education, Anhui University of Science & Technology
School of Mines, China University of Mining and Technology

以陕西某千米深井巨厚关键层下采场冲击矿压显现为工程背景,分析了巨厚关键层矿震发育及采场冲击显现特征,采场第4、5工作面回采时巨厚关键层内矿震发育逐渐覆盖巨厚关键层全厚范围,且巨厚关键层下冲击显现主要发生在第4、5个工作面走向中部区域并监测到高能矿震。研究了巨厚关键层下采场覆岩结构及围岩应力演化特征并揭示了巨厚关键层对围岩动静载应力的作用机制。研究结果表明:巨厚关键层下采场第4、5工作面回采时,巨厚亚关键层和主关键层分别发生破断运动,顶板形成大尺度悬臂-铰接结构,其承担上覆载荷并转移至相邻实体煤区域,导致采场周围煤岩体静载应力显著升高;采动影响下大尺度悬臂-铰接结构发生多岩层协同破断,产生高能矿震动载扰动作用,导致高应力煤体动力失稳,冲击风险显著增加。提出了巨厚关键层下冲击矿压顶板深孔预裂爆破防治方案,实践结果表明该方案能够明显减小工作面顶板来压步距和矿震活动强度,显著降低冲击风险。

Taking rockburst occurrence in a large-scale stope under extra-thick key strata in Shaanxi Province as the engineering background, mining-induced seismicity in extra-thick key strata and rockburst in longwall faces was investigated. During the recovery of the 4th and 5th longwall faces, min- ing-induced seismicity gradually arose and eventually covered the whole extra-thick key strata. Rockburst occurred in the middle area of the 4th and 5th longwall faces along the strike direction, and high-energy seismicity was detected simultaneously. The collapse behavior, roof strata structure, and abutment stressevolution of the large-scale stope under extra-thick key strata were analyzed, and the effect of extra-thick key strata on the static and dynamic stresses of surrounding rock was revealed. The following beneficial results were obtained. With the recovery of the 4th and 5th longwall faces, primary and secondary extra- thick key strata break, respectively, and a large-scale cantilever-articulated beam structure is formed in the roof. This structure serves to bear the overburden load and shifts it to the adjacent coal and rock mass, leading to a notable increase in the static stress there. Under mining disturbances, multiple rock strata in the large-scale cantilever-articulated structure break collaboratively and trigger high-energy seis- micity, which exerts dynamic disturbances on the overstressed coal and rock mass and significantly pro- motes rockburst risk. Accordingly, a strategy for prevention and control of rockburst by deep-hole pre- splitting blasting was proposed. The monitoring results indicate a remarkable decrease in both the periodic weighting distance and the mining-induced seismicity intensity, demonstrating that the strategy succeeds in effectively lowering rockburst risk.

国家自然科学基金项目(52304197,U21A20110);国家重点研发计划项目(2022YFC3004603);安徽理工大学引进人才基金项目(2022yjrc38);安徽省煤炭安全精准开采工程实验室开放课题基金项目(ESCMP202307)