深埋隧洞围岩水-力-损伤耦合的宏细观机制与多尺度建模方法

The macro-meso mechanism of coupled hydro-mechanical-damage processes in surrounding rocks is a key issue that needs to be addressed urgently for the areas of disaster prevention and mitigation for deep tunnels, and is also a fundamental subject in the field of rock mechanics. By using a comprehensive methodology of laboratory tests, theoretical analysis, numerical simulations as well as in-situ monitoring and inverse modeling, the project intends to give an insight into the dilatant damage and permeability evolution behaviors for surrounding rocks of deep tunnel in crystalline rocks under hydro-mechanical coupling condition from the perspective of multi-scale. An anisotropic damage model and a permeability evolution model will be presented with the consideration of the influence of structural alteration at different scales (such as fractures and microcracks), which will be able to capture the meso-mechanism of multi-scale structural damage evolution and its induced change in the permeability for fractured rocks. Then a mathematical model and a numerical method for coupled hydro-mechanical-damage processes in fractured rocks will be formulated. Finally, the coupled hydro-mechanical-damage processes under the condition of deep tunnel excavation will be simulated to capture the influences of the coupling property on the excavation disturbed effect of surrounding rocks, and then a synergetic control strategy of seepage flow, mechanical deformation and stability for deep tunnel under hydro-mechanical-damage coupling conditions will be studied. The research results will provide a significance theoretical contribution in better understanding the coupled hydro-mechanical-damage behaviors of fractured rocks, and also provide important practical values for geological disaster prevention and mitigation in deep tunnel engineering.

深埋隧洞围岩水-力-损伤耦合的宏细观机制是深埋隧洞工程灾害防治迫切需要解决的关键问题，也是岩石力学领域的重要基础性研究课题。本项目以结晶岩体中的深埋隧洞围岩为研究对象，采用试验、理论分析、数值模拟与监测反馈相结合的方法，从多尺度视角开展水-力耦合条件下裂隙岩体的损伤扩容机理和渗透特性演化规律研究，建立综合考虑岩体内部裂隙、微裂纹等不同尺度结构变化影响的深埋隧洞围岩各向异性损伤模型与渗透特性演化模型，揭示裂隙岩体多尺度结构损伤及其诱发的渗透特性演化的细观机制，建立裂隙岩体水-力-损伤耦合数学模型与三维有限元数值模拟方法，揭示岩体水-力-损伤耦合特性对深埋隧洞开挖扰动效应的影响，探讨水-力-损伤耦合条件下围岩渗流、变形与稳定协同控制策略。研究成果对于深化裂隙岩体水-力-损伤耦合机理研究具有重要理论意义，对于深埋隧洞工程地质灾害防治具有重要的应用价值。

本项目以深埋隧洞围岩水-力-损伤耦合特性为核心科学问题，从多尺度视角开展水力耦合作用下岩体各向异性损伤扩容机制与渗透性演化、岩体水-力-损伤耦合特性与多尺度建模方法以及深埋隧洞围岩开挖扰动效应模拟等方面内容的研究。主要研究成果如下：（1）建立了考虑层面、微裂纹等不同尺度结构变化影响的层状岩体损伤诱发的渗透性演化模型；（2）完成了不同渗透压作用下玄武岩的单轴与三轴压缩试验，分析了岩体强度、粘聚力、内摩擦角以及弹性模量等随渗透压的变化规律；（3）完成了湿干循环作用下泥岩的崩解试验，分析了水-岩相互作用对岩体物质组成、细观结构、吸水率等物理力学特性的影响；（4）完成了渗流场动态变化环境下土质试样的渗透试验，分析了土-水相互作用对土质试样颗粒级配与渗透性的影响；（5）建立了考虑微裂隙细观力学行为的岩石水力损伤耦合数值模型；（6）推导了基于岩体宏细观结构的层状岩体水力耦合数值模型，建立基于TOUGHREACT的三维数值仿真计算平台；（7）开展了地下工程洞室开挖、岩体注水等扰动作用下的数值模拟研究，分析了岩体多尺度结构特征与水力耦合效应对围岩扰动效应的影响。研究成果可为深部岩体工程安全和性能评价提供关键的理论和技术支持。