深部软弱围岩峰后流变-渗流耦合特性与失稳机理研究

The deep coal mining brings about the problems of post-peak large deformation and failure of surrounding rock of roadways under high hydro-mechanical conditions. The research on the rheology-seepage coupling properties of deep post-peak surrounding rock is of great significance. The post-peak state of deep soft rock (such as mudstone) is taken as the research object. The rheological properties and penetrability of deep post-peak rock would be identified by conducting the coupling rheological tests and permeability tests under rheology-seepage coupling conditions, and a post-peak rheology-seepage coupled constitutive model of deep soft rock is built by X-ray diffraction, SEM scanning and Triaxial compression tests, which takes into account the factors such as mineral composition, meso-structure and seepage. Then, the unloading numerical simulation of deep water-enriched roadway excavation under different engineering geological environment is carried out. Furthermore, the evolution characteristics of stress field, displacement field, fracture zone and seepage field would be explored to reveal the characteristics with the post-peak large deformation and the mechanisms of the failure with surrounding rocks of deep water-enriched roadways. Finally, a criterion for failure and instability of surrounding rock considering accumulation of rheological deformation and non-Darcy seepage factor is established to reveal the rheological instability mechanism of post-peak surrounding rock of deep water-enriched roadway. The achievements of this research can provide theoretical reference and a new technical way to resolve the control problems of surrounding rocks of deep water-enriched roadways.

深部富水巷道在高地应力、强渗透水压的长期耦合作用下极易发生峰后流变大变形与失稳事故，深入探究深部软弱围岩峰后流变-渗流耦合特性意义重大。本项目以深部软弱岩石（泥岩）峰后状态为视角点，拟通过开展深部软弱岩石峰后流变-渗流耦合试验，查明流变-渗流耦合作用下深部软弱岩石峰后的流变特性与渗透特性，结合X射线衍射、SEM电镜扫描和三轴压缩试验，建立考虑矿物组分、细观结构和渗流作用等影响因素的深部软弱岩石峰后流变-渗流耦合本构模型。在此基础上，开展不同工程地质环境影响下的深部富水巷道开挖卸荷数值模拟，系统研究围岩应力场、位移场、破裂区和渗流场的时空演化规律，建立考虑流变变形累积和非Darcy渗流因子的深部富水巷道围岩破坏失稳判据，揭示深部富水巷道围岩峰后流变失稳机理。研究成果可为解决我国深部富水巷道围岩控制难题提供新的技术途径和理论基础。

深部富水巷道在高地应力、强渗透水压的长期耦合作用下极易发生峰后流变大变形与失稳事故，深入探究深部软弱围岩峰后流变-渗流耦合特性意义重大。本项目围绕深部软弱岩石峰后流变-渗流耦合本构关系、深部富水巷道围岩峰后流变失稳判据等2个关键科学问题，开展了深部软弱岩石峰后流变-渗流耦合特性试验、深部软弱岩石峰后流变-渗流耦合本构关系及数值方法、深部富水巷道围岩峰后流变变形特征与失稳机理等3个方面的研究内容。首先，开展X射线衍射、SEM电镜扫描和三轴压缩试验，获得了矿物组分、微观结构与三轴压缩强度的关系。其次，开展了软弱岩石峰后流变-渗流耦合试验，揭示了流变-渗流耦合作用下深部软弱岩石峰后的流变特性与渗透特性，查明了流变-渗流耦合作用下岩石流变破坏形式和微细观破裂机理。再次，基于软弱岩石峰后流变-渗流耦合试验结果，引入非线性粘塑性体改进西原模型，建立了考虑峰后应变软化和渗流作用的岩石峰后非线性流变模型，利用积分变换推导了软弱岩石峰后非线性流变三维本构方程，并与流-固耦合理论相结合，建立了岩石峰后非线性流变-渗流耦合模型，并将其嵌入FLAC3D软件中，系统研究了深部富水巷道围岩应力场、位移场、塑性区分布及渗流场随时间的演化特征，分析了不同孔隙水压和时间等因素对巷道围岩流变变形、破坏形态和渗流行为的影响规律。然后，基于室内试验、现场监测和数值模拟结果，采用突变学和非Darcy渗流动力学理论，建立了考虑流变变形累积和非Darcy渗流因子的深部富水巷道围岩破坏失稳判据，揭示了深部富水巷道围岩峰后流变失稳机理。最后，针对深部富水巷道围岩的流变变形特征，提出了“让压-锚注”耦合控制技术，研究了不同让压距离、不同让压载荷以及不同注浆时机对深部富水巷道围岩应力、变形、塑性区分布的影响规律，揭示了“让压-锚注”耦合控制机理。研究成果可为解决我国深部富水巷道围岩控制难题提供新的技术途径和理论基础。