煤层顶板多种灾害发生机理与协同防治技术

Mechanisms and collaborative prevention and control techniques for various disasters in coal seam roofs

  • 摘要:
    目的 基于我国煤层多期沉积−构造演化形成的煤与瓦斯突出、突水、冲击地压等多灾害共生环境,针对深部开采条件下高地应力–高水压–强采动耦合诱发的顶板多灾害链式演化难题,系统开展了煤层顶板多动力灾害耦合机制与协同防治技术研究。
    方法 通过区域构造特征分析与赋煤构造单元划分,综合运用地质力学分析、灾害演化分析及技术模式构建等方法,系统揭示了煤层顶板多动力灾害的耦合作用机制,创新构建多灾害协同防控技术体系。
    结果和结论 (1) 随着开采深度增加,顶板灾害由单一模式向瓦斯–冲击地压–水害复合模式转变,深部“三高一扰动”环境通过应力重分布–裂隙扩展–能量积聚的链式作用,诱发冲击启动、水气互馈等灾害耦合效应;(2) 突破传统冲击–瓦斯二元耦合研究框架,系统建立了包含巨厚含水层致冲、离层水–厚硬顶板联动等多灾害耦合模型,阐明了采动裂隙网络贯通诱发气液运移–能量释放的跨灾耦合机理;(3) 创新提出“分源辨识–分类调控–协同防治”的技术路径,研发形成包含定向长钻孔分段压裂、地面L型井群组改造等关键技术的“井上下联动、区域局部协同”五种防控模式。该成果为破解深部开采多灾种协同防控难题提供了理论依据和技术路径。

     

    Abstract:
    Objective The multistage sedimentary and tectonic evolution of coal seams in China has led to the formation of environments with the coexistence of multiple disasters including gas outbursts, water inrushes, and rock bursts. To address the chain evolution of these disasters induced by the coupling of high in situ stress, high water pressure, and intense mining under the condition of deep coal mining, this study systematically investigated the coupling mechanisms and collaborative prevention and control techniques of multiple dynamic disasters in coal seam roofs.
    Methods Based on the regional tectonic characteristics and the delineation of coal-bearing tectonic units, this study systematically revealed the coupling mechanisms of multiple dynamic disasters in coal seam roofs by integrating geomechanical analysis, disaster evolution analysis, and technical mode construction. Accordingly, this study innovatively developed the technology system for collaborative prevention and control of multiple disasters.
    Results and Conclusions  The results indicate that with an increase in the coal mining depth, disasters in coal seam roofs have evolved from a single mode to a composite mode consisting of gas outbursts, rock bursts, and water disasters. In deep environments characterized by high in situ stress, high formation temperature, high water pressure, and strong mining disturbance, the chain effects of stress redistribution, fracture propagation, and energy accumulation induce the coupling effects of disasters such as rock burst initiation and water-gas interactions. By transcending the traditional binary coupling framework of rock bursts and gas outbursts, this study systematically developed a coupling model of multiple disasters including significantly thick aquifer-induced rock bursts and the linkage between water in the detachment layer and thick, hard coal seam roofs. Using this model, this study clarified the cross-disaster coupling mechanisms due to the gas and liquid migration and energy release induced by the interconnection of mining-induced fracture networks. This study innovatively proposed a technique path integrating source-based identification, classification-based control, and collaborative prevention and control. Furthermore, it developed five prevention and control modes characterized by surface-underground linkage and regional-local collaboration, involving critical technologies like multistage fracturing using directional long boreholes and the modification of L-shaped surface well groups. The results of this study will provide a theoretical basis and technical path for addressing the challenge of the collaborative prevention and control of multiple disasters in deep coal mining.

     

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