School of Energy and Mining Engineering, China University of Mining and Technology-Beijing, Beijing, 100083, China.
State Key Laboratory of Water Resource Protection and Utilization in Coal Mining, Beijing, 102209, China.
Sci Rep. 2022 May 14;12(1):7994. doi: 10.1038/s41598-022-12023-9.
Starting from the source of mining, scientific understanding of surface damage law and assessment method in longwall mining of shallow coal seam is conducive to solving the problems of geological hazards and deterioration of the ecological environment, and promoting the coordinated development of efficient coal mining and environmental protection. Based on numerical simulation and theoretical analysis, the surface damage process and spatiotemporal evolution of fracture field are discussed. The influencing factors and assessment method of surface damage are clarified. The results show that surface damage undergone the immediate roof caving stage, the fracture and instability stage of main roof, the spatial amplification stage of separation layer, the instability stage of surface damage control layer and the mining damage stability stage. Under the critical extraction condition, the cracks above the goaf are divided into the crack area outside the cut, the crack area inside the cut, the re-compaction area in the middle goaf, the crack area behind the longwall face, and the crack area in front of the longwall face. The overburden reaches critical failure ahead of surface critical mining. The sensitivity of loose layer thickness to surface subsidence coefficient is greater than that of mining thickness to surface subsidence coefficient. Surface damage control should be adjusted to local conditions, and finally realize zoning treatment and zoning repair. Through the three-step method of "longwall face rapid advancing method, local grouting reinforcement overburden method and zoning treatment ground fissures method", the surface damage control of 12,401 longwall face is realized. This research provides theoretical guidance and application value for surface ecological restoration in similar mining area.
从开采源头出发，深入研究浅埋煤层长壁开采的地表移动破坏规律及评价方法，有利于解决浅埋煤层开采地质灾害问题与生态环境恶化问题，促进高效采矿与环境保护协调发展。基于数值模拟和理论分析，讨论了地表损伤过程和裂缝场的时空演化，阐明了地表损伤的影响因素和评价方法。研究结果表明，地表损伤经历了直接顶垮落阶段、基本顶断裂失稳阶段、离层空间扩容阶段、覆岩破坏控制层失稳阶段和采动稳定阶段。在临界开采条件下，采空区上方裂缝分为采空区外侧裂缝区、采空区内侧裂缝区、采空区中部压实区、工作面后方裂缝区和工作面前方裂缝区。上覆岩层在地表临界开采前达到临界破坏。松散层厚度对地表下沉系数的敏感性大于开采厚度对地表下沉系数的敏感性。应因地制宜地调整地表破坏控制措施，最终实现分区处理和分区修复。通过“工作面快速推进法、覆岩局部注浆加固法和分区治理地裂缝法”三步法，实现了 12401 工作面的地表破坏控制。该研究为类似采矿区的地表生态恢复提供了理论指导和应用价值。
