多场耦合时滞效应下深井断裂构造底板滞后突水机理

Aiming at lagging water inrush problem caused by time-delay coupling effect of stress field - damage field - seepage field in the process of deep mining, this project conducts further research on mechanism of lagging water inrush along faulted structure, which is guided by multi-field coupling theory, and combined with site investigation, field measurement, theoretical analysis, laboratory experiments and numerical simulation. First of all, the effect law of water content, structural surface dip and water pressure on the shear creep characteristics are studied by true three-axis shear creep test under multi-stage loading, and creep mechanics model are established to study mechanics mechanism of time-delay effect about stress field - damage field- seepage field coupling; Secondly, mineral composition and microstructure of fault material are carried out by X-ray diffraction experiment and scanning electron microscope experiment respectively, and the influence law of softening damage characteristics to the anti-permeability and anti-shear performance are further conducted by permeation experiment and geotechnical test; after that, the engineering response characteristics of fracture permeability under mining disturbance are discussed by permeability coefficient field measurement based on double-end seal detector under downhole drilling; Finally, the water inrush process under time-delay effect of multi-field coupling is simulated by FLAC3D software in order to reveal the mechanism of lagging water inrush, so as to provide a theoretical basis for the prevention and treatment of water inrush disaster in deep mine.

针对深井采掘过程中应力场-损伤场-渗流场耦合时滞效应下导致的断裂构造滞后突水问题，本项目以多场耦合为理论指导，采用现场调研、现场实测、理论分析、室内实验、数值模拟等方法对断裂构造滞后突水机理进行研究。首先，通过真三轴分级加载剪切蠕变实验研究含水率、结构面倾角和渗透压对试件剪切蠕变特征的影响规律，建立断裂构造蠕滑力学模型，揭示应力场-损伤场-渗流场耦合时滞效应的力学机制；其次，采用X射线衍射实验和扫描电镜实验进行断层物质矿物成分鉴定和微观结构观察，结合渗透实验和土工实验研究断层物质软化损伤特性对断裂构造抗剪抗渗性能的影响规律；而后，采用井下钻孔双端封堵探测仪，研究采掘扰动下断裂构造渗透性能的工程响应特征；最后，基于FLAC3D软件和应力-损伤-渗流-时间耦合关系进行突水过程模拟，揭示多场耦合时滞效应下滞后突水机理，为深井突水灾害防治提供理论依据。

针对深井采掘过程中多场耦合时滞效应下导致的断裂构造滞后突水问题，围绕多场耦合时滞效应下断裂构造摩擦滑动的力学机制、承压水导升过程中断层物质软化损伤特性及其对抗剪抗渗性能的影响规律、多场耦合效应下渗透系数动态演变过程及断裂构造渗透性能的工程响应特征、多场耦合时滞效应下突水过程数值仿真研究等研究内容，按照预期计划采用现场调研、理论分析、室内实验、数值模拟等手段，按时完成相关部分的研究内容，计划执行情况良好。. 主要成果如下：. ①在渗流水水压力作用下，裂隙面受有效剪应力增大，裂隙尖端应力强度因子提高，裂隙运动提前启动，加速裂隙扩展发育。. ②渗流水对岩体发生软化损伤作用，降低岩石抵抗裂隙扩展的能力。随着断层物质中粘土矿物含量的增大，破坏方式由剪切流动破坏转向膨胀破坏，在破坏过程中，粘土含量较小的试件，其渗透率先减小后增大势，粘土含量较大的试件由于以膨胀破坏为主，没有渗流通道的形成，其渗透率一直减小。. ③当围压一定时，裂纹起裂、扩展至最终破坏速度与其内部孔隙水压成正相关。低水平围压区内易造成承压水导升带内翼裂纹纵向扩展和渗透性升高。. ④围压越大，其裂隙扩展角会随之变小，裂隙扩展偏于横向发育，其在试件内部难以形成垂向贯通裂隙，导致渗透率会随着压应力的增加而变小。. ⑤通过建立的应力场-渗流场耦合模型进行断裂滞后突水仿真模拟，真实地模拟现场地质条件，对类似地质条件下煤层底板断裂滞后突水进行早期预报研究，提出受断裂影响的深部煤层预防滞后突水的安全技术措施和技术参数。. ⑥研发了动水条件下断裂构造注浆堵水材料，提出了临时控制与永久治理、注浆加固与注浆堵水、井下治理与井上治理相结合的断裂构造滞后突水治理方案。