特厚煤层冲击地压发生机理与危险性预警研究

With the increase of the mining depths of coal mines in middle, southwestern and eastern China, the hazards of rockburst, mine seismicity and roof weighting are becoming increasingly severe, which leads to the decrease of coal production year by year, and the swift transfer of coal mining to the western China. However, the extra-thick coal seams in coal mines in Neimenggu, Xinjiang, Shanxi and Gansu Province have already encountered a number of rockbursts at the depth of around 300 m. Rockburst hazard has become the major threat to the coal mining transfer to the west China. The analyses of rockbursts occurring in the coal mines in western China have revealed that the mechanism of rockbursts and their risk early warning in extra-thick coal seams are different from that in general coal seams. Due to the lack of special research, there is no effective rockburst prevention theory for the extra-thick coal seams. In comparison with thin coal seams, rockbursts in extra-thick coal seams begin to occur at a smaller depth but more intensely, and are more sensitive to the stress environment. This proposed project focuses on studying the mechanism of rockbursts in extra-thick coal seams and its early warning methods. The occurrence mechanism of rockbursts in extra-thick coal seams are explored by establishing the models of “thick elastic strata structure above extra-thick coal seams” and “uneven parting in extra-thick coal seams”. Based on the mechanism, the most sensitive rockburst precursors in extra-thick coal seams are discussed, which provides a theoretical basis for the rockburst early warning.

随着我国中部、西南和东部煤矿开采深度加大和条件的恶化，冲击地压、矿震、顶板大面积来压等动力灾害越来越严重，产量逐年下降，煤矿开采的重点正快速向西部转移。然而，内蒙、新疆、陕西、甘肃等省区特厚煤层已经在300米左右的深度发生了多起冲击地压事故，冲击地压已经成为煤炭主战场西移的主要障碍之一。事故分析揭示了特厚煤层冲击地压的发生机理和危险性预警不同于一般煤层，但目前缺乏这方面的专门研究，导致特厚煤层矿井缺乏有效的防冲理论指导，冲击威胁十分严重。本项目针对特厚煤层矿井临界冲击深度减小、应力敏感性增强和冲击规模加大的特点，重点研究特厚煤层的冲击机理和预警方法。通过建立“特厚煤层厚弹性地层结构”和“特厚煤层不均匀夹矸地层结构”模型，探索特厚煤层冲击发生机理，在此基础上，研究特厚煤层最敏感的冲击前兆指标，为冲击危险性预警提供理论基础，试图破解当前特厚煤层矿井预警方法和指标不可靠的难题。

随着我国中东部煤炭资源逐渐枯竭，国家煤炭产能快速向资源埋藏深度较小的西部转移。近年来，西部多个矿区的特厚软硬复合煤层巷道掘进过程中发生冲击地压灾害，严重影响了矿井生产安全和国家能源供给。本项目建立了不同煤层厚度围岩能量计算模型和夹矸煤层应力分布模型，得到了在不同埋深条件下煤层与岩层的能量密度比值在1.8~2.3之间，揭示了特厚煤层工作面临界冲击深度减小和更容易发生冲击的机理，提出了考虑煤层厚度和冲击倾向性的冲击危险性评价方法。通过对多起“应力腐蚀型”冲击事故的调查研究发现该类冲击具有自发性和时滞性的特点，建立了特厚煤层围岩“应力腐蚀”过程的动态模型，揭示了“应力腐蚀型”冲击的孕育条件和发生机理，通过现场监测得到了特厚煤层“应力腐蚀”导致冲击危险性增加的前兆特征，建立了特厚煤层冲击地压多参量综合监测预警系统，提出了特厚煤层冲击危险预警方法与指标体系。.课题组研发了适用于特厚煤层冲击地压防治的多参量综合监测预警装备，已经在新疆、内蒙等多个西部地区特厚煤层矿井进行了成功应用，为特厚煤层矿井开采冲击地压监测预警提供了理论和工程依据。因此，本项目对特厚煤层冲击地压灾害的发生机理及监测预警，具有重要的现实意义。