应力恢复对采动裂隙岩体结构及阻隔水能力演化的影响机制

The closing effect of the mining-induced fractured rock mass has a great important engineering and theoretical significance on the repair of the groundwater seepage system in the western ecologically fragile mining area, the residual coal seam re-mining in the eastern aging coal-mines, and the prediction and prevention of water inflow. The mining-induced fractured rock mass is taken as the object of study, the cover stress re-establishment is set as the main control factor. The soft and hard rock structures composed with aquifers and aquiclude are set as the engineering geological conditions. The physical model test, theoretical analysis, experiment and in-situ monitoring are used in this study, and the PIV technology and the method of fractured rock seepage test are applied in the research process. The main study contents include refining the cover stress evolution characteristics in the fractured zone after coal mining, and derivation of time and space functional models for the cover stress re-establishment in the fractured rock mass after coal mining; obtaining the quantitative distribution and evolution characteristics of void ratios and the local strain concentration characteristics in the process of fracture sprouting, propagation and closure, and building the fracture medium model for the fractured rock mass; revelation the effect of structure on permeability evolution under the conditions of lateral restraint and axial loading, and getting the engineering geological model for water resistance recovery of mining-induced fractured rock mass.

研究采动裂隙岩体压缩弥合效应对西部生态脆弱矿区地下水渗流系统的修复、东部衰老矿井裂隙岩体下残煤复采及矿井涌水量预测与防治等具有重要的工程及理论指导意义。本项目针对采动裂隙岩体阻隔水能力恢复的现象，以其应力恢复为主导控制因素，以含水层下若干隔水、导水的煤层软硬覆岩结构为工程地质条件。通过模型试验、理论分析、试验研究并结合现场监测，采用粒子图像测速(PIV)技术及裂隙岩体渗流试验方法，研究采后裂隙岩体应力恢复的特点和规律，建立采动裂隙岩体应力恢复的时空分布函数模型；获得裂隙岩体空隙率定量分布及演化特征，裂隙萌生、发育及闭合过程中局部应变集中特征，建立采动裂隙岩体的裂隙介质模型；揭示裂隙岩体在侧向约束、轴向加载条件下的结构效应对渗透性转化的影响机理，获取采动裂隙岩体阻隔水能力恢复的工程地质模式。

采动裂隙岩体随煤层开采距离及时间具有压缩弥合效应，在应力恢复作用下其结构演化是一项复杂的四维空间问题，本项目通过模型试验、理论分析、砂槽试验并结合现场监测，采用了粒子图像测速(PIV)技术及裂隙岩体渗流试验方法，研究了采后裂隙岩体应力恢复的特点和规律，建立了采动裂隙岩体应力恢复的时空分布函数模型；获得了裂隙岩体空隙率定量分布及演化特征，建立了采动裂隙岩体的裂隙介质模型；揭示了裂隙岩体在侧向约束、轴向加载条件下的结构效应对渗透性转化的影响机理，获取了采动裂隙岩体阻隔水能力恢复的工程地质模式，修正了含水层底部疏放水井非完整井涌水量Dupuit计算公式并揭示了其渗流特征，研究结果对西部生态脆弱矿区地下水渗流系统的修复、东部衰老矿井裂隙岩体下残煤复采及矿井涌水量预测与防治具有重要的工程及理论指导意义。