深埋高应力条件下卸荷诱发高边墙地下洞室围岩劈裂的时效性演化机制研究

With the development of infrastructure, the underground engineering of hydropower station in south west of China arose feature of large-scale, complex geology condition, deep overburden and high in-situ stress. For the high ratio of in-situ stress to strength of rock mass, nonlinear mechanical behavior of the surrounding rock mass with the large deformation caused by time-dependent splitting failure appeared during excavation, with the representative Jinping I hydropower station. In this research, 3D geological mechanics model test, theoretical analysis and numerical simulation will be combined to reveal the strength condition and deformation mechanism of time-dependent splitting failure. Loading-unloading rheological experiment with crack included rock similar material and 3D geological mechanics model test with analogical material will be performed to explore the feature of time-dependent splitting damage, to reveal mechanical law and evolution mechanism of splitting. On the basis of in-situ monitoring and model test, fracture mechanics, damage mechanics, rheology mechanics and energy dissipation will be adopted to develop failure criterion and constitutive model of time-dependent splitting of jointed rock mass under high stress condition. Furthermore, numerical analysis method will be proposed and utilized to analyze and evaluate the stability of rock mass of underground caverns. This research will be meaningful and practical to the engineering geology and rock mass stability of deep underground engineering.

随着我国基础建设高速发展，西部水电建设中地下工程呈现出规模空前、工程地质条件复杂、大埋深和高地应力等特点。以锦屏一级水电站为代表的高边墙地下洞室围岩由于具备低强度应力比特征，在开挖卸荷过程中诱发了围岩时效劈裂大变形的非线性力学行为。本课题拟采用模型试验、理论和数值模拟等综合分析方法揭示时效劈裂强度破坏条件和变形机制。通过开展含断续裂隙类岩试件卸荷三轴流变试验和相似材料真三维地质力学模型试验，探索时效损伤破裂特征，揭示围岩时效劈裂力学变化规律与演化机制。在现场监测、系统模型试验研究的基础上，通过断裂、损伤力学，流变力学和能量耗散等相关理论研究建立反映高应力条件下裂隙岩体卸荷时效损伤劈裂准则和本构模型，并建立模拟时效劈裂的数值分析方法和计算平台。最终实现应用于工程实践的地下洞室围岩时效劈裂安全性的分析和评价方法。本研究对深部水电工程地质学及岩体工程稳定学领域有重要的理论意义和实际工程应用价值。

随着我国基础建设高速发展，西部水电建设中地下工程呈现出规模空前、工程地质条件复杂、大埋深和高地应力等特点。以锦屏一级水电站为代表的高边墙地下洞室围岩由于具备低强度应力比特征，在开挖卸荷过程中诱发了围岩时效劈裂大变形的非线性力学行为。本课题拟采用模型试验、理论和数值模拟等综合分析方法揭示时效劈裂强度破坏条件和变形机制。通过开展含断续裂隙类岩试件卸荷三轴流变试验和相似材料真三维地质力学模型试验，探索时效损伤破裂特征，揭示围岩时效劈裂力学变化规律与演化机制。在现场监测、系统模型试验研究的基础上，通过断裂、损伤力学，流变力学和能量耗散等相关理论研究建立反映高应力条件下裂隙岩体卸荷时效损伤劈裂准则和本构模型，并建立模拟时效劈裂的数值分析方法和计算平台。最终实现应用于工程实践的地下洞室围岩时效劈裂安全性的分析和评价方法。本研究对深部水电工程地质学及岩体工程稳定学领域有重要的理论意义和实际工程应用价值。