西部矿区短壁块段式采煤覆岩应力-裂隙-渗流耦合机理与保水技术研究

Shortwall block mining has become an effective technical approach of coal under village, railway line and river, irregular block coal pillar and has been popularized and applied on a large scale, and has given good consideration to the safe and efficient mining of coal and the protection of water resources. But it has a potential effect on water resources loss in the process of exploitation. On the basis of systematically analyzing the mechanism of overburden fracture propagation and the characteristics of space-time distribution of fracture in shortwall block mining, the main controlling factors affecting the development of overburden fracture in shortwall block mining are determined. The variation of overburden stress distribution and fracture development under the interaction of mining height, protection pillar width between blocks, mining depth, key layer location, etc. The law of groundwater seepage is revealed under the coupling conditions of different seepage field and stress field. Based on the background of ecologically fragile mining area in western China, the prediction and evaluation model of shortwall block mining on water resources loss is established, and the control mechanism of overburden fracture development is put forward, and the theory and method system of shortwall block mining water conservation is constructed. This project will provide scientific theoretical basis and guidance for scientific and effective prevention and control of water resources loss caused by shortwall block mining.

短壁块段式采煤成为“三下压煤”和不规则块段等资源的有效技术途径并得到了较大规模的推广应用，并良好的兼顾了煤炭安全高效开采和水资源保护，但在开采过程中对水资源流失具有潜在的影响。在系统分析短壁块段式采煤覆岩裂隙扩展力学机制及其时空分布特征的基础上，确定影响短壁块段式采煤覆岩裂隙发育的主控因素，深入研究采高、块段间保护煤柱宽度、开采深度、关键层位置等多因素交互影响下的覆岩应力分布变化和裂隙发育规律，并揭示了不同渗流场和应力场等多场耦合条件下地下水渗流规律。结合西部生态脆弱矿区背景，建立短壁块段式采煤对水资源流失的预测和评估模型，提出覆岩裂隙发育控制机制，构建短壁块段式保水开采理论与方法体系。本项目研究将为科学有效的预防、控制短壁块段式采煤过程中所引起的水资源流失问题提供科学理论依据与指导。

煤炭开采过程中，造成上覆岩层的剧烈运动和大范围的破坏是不可避免的，造成水土流失严重以及生态环境脆弱等一系列的环境问题。短壁块段式采煤技术作为一种我国自主研发的绿色开采技术，可以有效地兼顾煤炭安全开采和水资源保护。主要研究内容有：（1）短壁块段式采煤上覆岩层裂隙演化机理及力学响应：确定了影响采场覆岩活动和导水裂隙发育主控因素，并通过分析短壁块段式采煤工作面布置特点和覆岩破坏空间结构特征，建立了短壁块段式采场覆岩导水裂隙扩展的弹性地基叠合梁力学模型。（2）多因素交互影响下块段式采煤覆岩应力分布特征及裂隙发育规律：研究了不同主控因素条件下短壁块段式采场覆岩移动时空演化特征及导水裂隙发育规律，并通过利用多元非线性回归分析方法建立短壁块段式采煤导水裂隙带高度预测体系。（3）多场耦合作用下短壁块段式采煤裂隙岩体渗流特征：进行了不同系统参数下的岩石三轴压缩渗流试验，研究了各参数影响下岩石变形破坏特征和渗流演化规律。通过数值模拟分析块段开采后隔水层变形破坏特征及渗流演化规律，实现对覆岩裂隙岩体渗流特征的定量描述。（4）短壁块段式采煤对水资源影响的防控体系。结合短壁块段式采煤工艺采出率相关指标与隔水层自身阻水特征，构建短壁块段式采煤“采出率-水资源防护”综合评价模型，同时通过短壁块段式充填采煤工艺实现覆岩裂隙、隔水层渗流控制，形成“防控一体化”的短壁块段式采煤对水资源影响的防控体系。