煤矿采空区储水结构强度的动态损伤机理

Water storage in the gob of coal mine is a crucially important technical methods to reasonably conserve and utilise mining water resources and achieve the green mining coordinating with eco-system. The physical and mechanical properties of gob and its coal-rock boundaries vary with water-intrusion. Meanwhile, overlying strata movement will have a significant effect on coal-rock accumulation shape, water pressure and structural stability of water storage. Therefore, taking typically coal mines conditions located in ecologically vulnerable area in western China as our emphasis, we propose our primary research approaches as follows. First, characteristics of coal-rock damage and rheology under water intrusion will be observed, after which properties of coal-rock components, its microstructures and its deformation will be studied in terms of different coal-rock granular sizes, the mixture of various lithological rocks and recycling water intrusion. The intrinsic mechanism of varying storage space inside gob will be demonstrated during the dynamic process of water storage-transfer-storage and the damaging laws of storage structure will also be illustrated. Secondly, dynamic load effect aroused by changing gob space also will be depicted during the deformation of overlying strata movement and then we illustrate the changing pattern of stress in the gob. Based on the grasp of changing regulation of gob space and its stress, we will propose strength criterion and methodology of storage structure design for water resource and thus attain the stability of storage structure, which has a vitally scientific and engineering significance for water storage and utilisation in coal mines.

煤矿采空区储水是合理保护和利用矿井水资源、实现与生态相协调的煤矿绿色开采的重要技术途径。水作用下采空区内及其边界煤岩体物理力学性质的改变，以及上覆岩层的运移，将对采空区内部煤岩体的堆积形态、水压及储水结构稳定性产生重要影响。本课题拟选取西部生态脆弱区典型的煤矿开采条件，研究浸水条件下煤岩体强度损伤、流变特征，探讨不同煤岩粒径、煤岩组合及淋滤条件下，煤岩组分、微结构变化规律及变形特征，揭示水资源储存-转移-储存动态过程中采空区储存空间变化的内在机制和水岩作用下储水结构的强度弱化规律；研究储水采空区上覆岩层在变形运动过程中，及采空区储存空间变化而引起的动载荷效应，揭示采空区储水结构应力演化规律；在掌握采空区储水过程中储存空间和应力变化的基础上，提出储水结构的强度设计准则和方法，以实现储水结构的稳定性。这对煤矿水资源的储存和合理利用具有重要的科学与工程意义。

煤炭开采引起顶板覆岩结构与完整性遭到破坏，致使水循环模式从层间径流为主向垂向径流为主转变，大部分顶板砂岩孔隙裂隙含水层及第四系松散含水层地下水渗（溃）入矿井采空区。针对西部生态脆弱区煤炭开采水资源转移过程中的岩石力学问题，研发了储水结构坝体及储水系数试验装置和煤系沉积岩无损浸水装置，深入研究了水作用下典型煤系沉积岩宏细观力学损伤和变形破坏机理，表征了不同含水率煤岩孔隙分布和微细观结构，通过统计损伤理论揭示了声发射特征对煤岩破坏的预测机制，得到了一定粒径匹配、岩性组合下煤岩压缩变形特征，提出了考虑水作用下修正的煤岩强度破坏准则和蠕变模型，揭示了煤矿采空区地下水库结构坝体应力-变形状态及强度弱化规律，构建了采空区储水结构坝体设计方法。研究成果在大柳塔、察哈素等多个煤矿得到推广应用，推进了地下水库建设关键工程科学问题的探索，为西部大型煤炭基地绿色开采提供理论和技术支持。研究成果发表SCI收录论文3篇、EI收录4、中文核心收录1篇；授权国家发明专利8件；获中国岩石力学与工程学会科学技术奖（科技进步奖）二等奖1项；在重要学术会议上作相关研究成果汇报7次；11名硕士研究生根据项目研究内容完成硕士学位论文。