特厚软硬复合煤层巷道掘进冲击地压发生机理研究

With the coal resources in the central and eastern China being gradually depleted, coal production activities are being shifted to the western China where the coal resources deposit at a relative shallower depth. However, recent years have seen frequent rock burst disasters when excavating in a particular type of coal seam in several western mines, i.e., the extra-thick soft-hard composite coal seam. This has seriously affected the mine production safety and the domestic energy supply. To prevent and control such rock burst disasters that occur in excavating the extra-thick soft-hard composite coal seams, a better understanding of their occurrence mechanism is thus required. To this end, this project first investigates the structural characteristics and the burst instability features of the surrounding rocks of roadways in the extra-thick soft-hard composite seam. Based on these, we then analyze the energy accumulation and dissipation mechanism of the surrounding rocks in conjunction with the mine pressure theory, rock mechanism experiments, numerical modelling and field monitoring. Subsequently, we discuss the failure characteristics and energy dissipation of the soft-hard composite coal under low uniaxial loading and unloading . Following this, we study the mechanism of the instability transfer and the resulting rockburst response in excavating the extra-thick soft-hard composite seam. Finally, we elucidate the relationship between the energy accumulation, instability transfer and rockburst occurrence in the surrounding rock in excavating the extra-thick soft-hard composite coal seam, and thus reveal the mechanism of rock burst in excavating the extra-thick soft-hard composite seam. Through this study, we intend to provide a theoretical basis for preventing and controlling the particular type of rockbursts that frequently occur in excavating the extra-thick soft-hard composite coal seam.

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。揭示特厚软硬复合煤层巷道掘进冲击地压发生机理是防治此类冲击地压灾害的前提。本项目结合特厚软硬复合煤层巷道围岩结构特征和冲击失稳特点，运用矿山压力理论，并通过岩石力学试验、数值模拟和现场监测等方法，首先分析特厚软硬复合煤层巷道掘进围岩能量集聚耗散机制，其次探讨软硬复合煤样低轴压卸荷冲击破坏特征与能量耗散规律，然后研究特厚软硬复合煤层巷道掘进失稳传递与冲击响应机制，从而掌握特厚软硬复合煤层巷道掘进围岩能量集聚、失稳传递与冲击显现之间的关系，最后揭示特厚软硬复合煤层巷道掘进冲击地压发生机理。期望通过研究，深入揭示特厚软硬复合煤层巷道掘进围岩能量集聚耗散和冲击响应机制，为此类冲击地压的防治提供理论依据。

随着我国煤矿开采深度加大和开采条件恶化，冲击地压、矿震等动力灾害越来越严重，煤炭主要产能快速向西部转移。近年来我国新疆、内蒙、陕西等省区特厚软硬复合煤层巷道掘进期间发生了多次恶性冲击地压事故，严重威胁了我国能源供给安全。事故分析揭示了特厚软硬复合煤层巷道掘进冲击地压发生机理不同于单一煤层，但目前缺乏相关研究，导致特厚软硬复合煤层矿井缺乏有效的防冲理论指导。本项目首先分析了特厚软硬复合煤层巷道围岩冲击特征，研究了特厚煤层巷道围岩冲击的煤厚效应，得到了特厚煤层巷道掘进围岩能量集聚耗散特征。其次开展了软硬复合煤样低轴压卸荷冲击破坏试验，掌握了煤样复合形式与低轴压卸荷冲击破坏特征及能量耗散规律，揭示了特厚软硬复合煤层巷道掘进先煤爆后冲击的机理。最后通过建立特厚软硬复合煤层巷道掘进发生冲击地压的动态力学模型，揭示了特厚软硬复合煤层巷道掘进软煤失稳向硬煤失稳传递的全过程及其冲击响应机制。项目研究成果可为我国西部特厚软硬复合煤层开采冲击地压防治提供理论基础。