差异水压复合含水层采动底板导升突水机理研究

This project will take the floor compound aquifers which in Carboniferous-Permian coal field during the lower coal group mining as the research object, and conduct the in-depth study on the mechanism of floor water inrush which under the conditions of different aquifer water yield property，different water pressure and affected by repeated mining disturbance. By establishing hydrogeological model of compound aquifers with different water yield property and mining floor stress distribution model under different pressure. This project will pay great attention to the mine pressure and seepage stress distribution law and the coupling relationship of the two which work on the floor through theoretical analysis, indoor experiments, field measurement, computer simulation and similar material simulation, etc. The confined aquifer's second rise fracture development rule will be revealed, compound aquifer mining floor water-irruption mode under different water pressure will be put forward, the mechanism of mining floor water inrush induced by water rise in compound aquifers under different water pressure will be illustrated. The research results of the project will give a supplement to the understanding of floor damage rule, solve the difficult problem of mining floor water inrush induced by water rise in compound aquifers under different water pressure. It will takes important theoretical and realistic significance for floor water-inrush theory and guiding prevention and control of floor water disasters in the mining with compound aquifers under different water pressure.

本课题将石炭-二叠纪煤田下组煤底板复合含水层作为研究对象，针对其在有差异富水、差异水压、采动扰动等条件下的底板导升突水机理问题进行深入研究。建立差异富水复合含水层水文地质模型和差异水压复合含水层采动底板应力分布模型，在此基础上采用理论分析、室内实验、数值模拟、相似材料模拟等方法，分析矿山压力和渗流应力底板分布规律及应-渗耦合关系；揭示应力-渗流耦合下的承压水含水层二次导升裂隙发育规律；提出差异水压复合含水层采动底板突水模式，阐明差异水压复合含水层采动底板导升突水机理，提出突水判据。本课题研究成果将补充以往对底板破坏发育特征和规律的认识，解决复合含水层差异水压下的采动底板导升突水难题，对丰富底板突水理论，指导差异水压复合含水层底板水害防治具有重要的理论和现实意义。

我国石炭-二叠纪煤田下组煤开采过程中面临的差异富水复合含水层、差异水压、采动矿山压力等条件下，疏放上覆薄层灰岩水导致与下伏奥灰含水层存在差异水压引发的煤层底板水害问题，开展了差异水压复合含水层采动底板突水机理的基础理论研究工作。构建了差异水压复合含水层水文地质模型和差异水压条件下的采动底板应力分布模型，通过数值模拟、相似材料模拟及现场实测分析了差异水压条件下强含水层二次导升裂隙发育特征，分析了差异水压和矿山压力作用下采场底板应力分布规律特征，计算了差异水压条件下强含水层二次导水的高度，提出了差异水压条件下复合含水层的突水模式，揭示了差异水压复合含水层的突水机理。依据项目申请书内容，经过系统研究，总体上达到预期目标，研究取得了如下成果：（1）根据华北型石炭二叠系煤田差异水压复合含水层的水文地质特征，建立了“煤层-隔水层-弱富水含水层-隔水层-强富水含水层”水文地质模型水文地质模型，分别为薄层灰岩疏放水、注浆改造薄层灰岩、原始复合含水层等三种条件下的差异水压复合含水层的模型。（2）构建了差异水压复合含水层采动底板破坏力学模型，求得差异水压条件下底板应力值及应力分布规律。分析差异水压存在时、底板隔水层厚度以及差异水压对于底板破坏的影响。（3）研发了差异水压顶板位移模拟试验平台，分析了不同差异水压对含水层顶板的影响，成果表明在压差最大为2KPa条件下，最大位移上升3mm。因此高承压含水层在上位含水层疏水降压条件下，更容易产生二次导升现象。（4）采用综合探查方法实测了差异水压复合含水层底板破坏深度，实测表明在差异水压条件下底板破坏深度可由14.2m直接增加至25.6m，在采动扰动条件下发生底板差异水压型突水。（5）阐述了差异水压复合含水层的突水机理，提出了三个差异水压复合含水层采动底板突水模式，即下位强富水含水层受疏水降压作用型突水、差异富水含水层采动底板破坏型突水、上位弱富水含水层高压注浆改造综合型突水模式。项目研究成果将为华北石炭二叠系煤田在煤层开采过程中的差异水压复合含水层底板水害的防治提供一定的基础理论依据。