临断层开采面围岩结构失稳演变规律及其诱发回采巷道冲击地压机制

The frequency and intensity of coal burst in roadway increase significantly as mining toward geological fault. Obviously, the surrounding rock shape of workface, as well as its unstable movement, is affected by the fault features. This project focuses on the characteristics of strata unstable movement and its impact on coal burst as mining toward fault. Firstly, a experiment will be designed to simulate the mining process near fault, and the experimental results will be analyzed comparatively with that of theoretical and numerical studies, then the features of fault, such as dip, throw and displacement, will be discussed for their influences on strata structure and its unstable movement. The combination pattern of static and dynamic stress caused by strata unstable movement will be studied with 3D numerical model. And further, experiments of coal failure test under different combination patterns of static and dynamic stress will be conducted. Features of coal failure process, such as stress, deformation, strength, crack and fracture, will be analyzed, and the constitutive model of coal will be constructed. Lastly, the mechanism of coal burst occurred in roadway as mining toward fault will be analyzed. The results of this project may provide new way to prevent coal burst as mining toward geological fault.

煤矿开采面临近断层构造时，回采巷道内冲击地压发生频次、破坏烈度显著增加。本项目从分析断层构造切割影响下开采面围岩结构特征入手，围绕临断层开采面围岩结构失稳演变规律及其对回采巷道冲击地压诱发机制展开研究。设计临断层开采组合结构体试验，结合理论分析、数值模拟方法，研究断层倾角、断距、落差等对开采面围岩结构几何特征影响，分析临断层开采面围岩结构类型及其随开采面推进失稳演变规律，获取临断层开采面围岩结构失稳对回采巷道不同区域煤体动静载扰动组合模式；开展不同动静载扰动组合模式下煤体变形破裂试验，分析煤体应力-应变、破坏强度、裂隙扩展、断口分形等宏细观特征，构建动静载扰动下煤体变形破裂本构模型，揭示临断层开采面围岩结构失稳对回采巷道冲击地压诱发机制。研究成果对临断层开采面回采巷道冲击地压危险性评价及防治工作具有重要意义。

项目针对断层构造影响区回采工作面两侧巷道冲击地压诱发机理及破坏特征开展了相关研究。首先理论分析了埋深、地质构造、开采布置等因素对回采巷道冲击危险性的影响特征，发现回采巷道在较高静载应力集中状态下易受动载应力扰动发生破坏失稳进而诱发冲击地压灾害，研究了静载应力与矿震应力波动载扰动叠加诱发断层弱面摩擦错动致震诱冲全过程；基于回采工作面开采扰动圈与断层弱面距离不同，将工作面回采对断层弱面应力扰动划分为远场开采扰动、近场开采扰动，基于工作面与断层弱面相对空间位置，将回采工作面划分为上盘开采、下盘开采，研究发现下盘采条件下断层弱面存在张拉离层危险，并分类别研究了不同开采条件下断层弱面剪切错动、张拉离层失稳准则；尝试采用组合煤岩试验方法、3D打印技术研究了双向等压条件下组合煤岩试件开挖应力、位移、震动响应特征；采用FLAC数值软件中Interface、C-M、Dynamic模型研究了断层活化对围岩的动静载扰动特征；最后基于赵楼矿1303工作面回采过Fd96正断层工程实例，设计采用大直径钻孔卸压降低冲击危险，并验证了防冲效果的有效性。研究成果对煤矿深部临断层开采冲击地压监测及防治具有重要理论和现实意义。