泄洪雾化诱发高边坡灾变失稳机理与灾变全过程数值模拟

The control of deformation and slope stability for high rock slopes under atomized rain conditions is the key guarantee for the construction and safety operation of high dam engineering in deep valley. In this project, high rock slopes located in the area of flood discharging atomization are taken as the case study. Aiming at high slope instability evolution process under atomized rain conditions, a comprehensive method combining field investigation, physical tests, theoretical analysis and numerical simulation is adopted to discover the mechanism of water-air seepage through high rock slopes, the evolution process of stability of rock slopes and the dynamic mechanism for the inoculation, occurrence and evolution of catastrophe. A coupled rain infiltration-overland flow model and a coupled two-phase flow-deformation model for rock mass under atomized rain conditions will be established. Then we will study progressive failure process and instability dynamic mechanism of slopes under rain seepage conditions, and propose an improved discontinuous deformation analysis method which can describe two-phase flow-deformation coupling effects and progressive failure process of rock mass. A numerical software modelling the whole process of progressive failure, instability occurring and landslide movement will be developed. This project will provide a theoretical reference and technical support for the design, the construction and the operation of high rock slopes under atomized rain conditions in large scale hydropower projects.

泄洪雾化区高边坡是深切河谷高坝枢纽工程的有机组成部分，其变形与稳定性控制是高坝工程建设与运行安全的重要保障。本项目以高坝泄洪雾化影响范围内的高边坡为研究对象，以雾化降雨入渗诱发高边坡灾变孕育演化全过程为研究主线，采用现场调查、室内试验、理论分析和数值模拟相结合的研究方法，揭示雾化降雨作用下高边坡渗流运动机理、稳定性演化规律、滑坡灾变孕育演化的动力学机制，建立边坡雾化降雨入渗-坡面产流的联合计算模型、边坡岩体水气渗流-变形耦合计算模型。通过研究雾化降雨入渗作用下边坡岩体的渐进破坏过程与灾变动力学机制，提出考虑水气渗流-变形耦合作用、并可模拟边坡渐进破坏过程的非连续变形分析方法，研发边坡渐进破坏、失稳启动及滑坡触发后运动全过程的数值模拟软件，为大型水电工程泄洪雾化区高边坡设计、施工和运行提供理论基础和技术支撑。

泄洪雾化区高边坡是深切河谷高坝枢纽工程的有机组成部分，其变形与稳定性控制是高坝工程建设与运行安全的重要保障。本项目以高坝泄洪雾化影响范围内的高边坡为研究对象，以雾化降雨入渗诱发高边坡灾变孕育演化全过程为研究主线，基于现场地质调查、结构面测量、裂隙取样和室内试验，研究单裂隙及交差裂隙非线性渗流机理、水气两相渗流的吸持机理，确定结构面粗糙度对水气两相毛细压力、接触角及界面曲率的内在联系，建立了粗糙裂隙非线性渗流细观分析模型和水气两相渗流分析模型；通过开展结构面在法向和剪切变形条件下单裂隙渗流运动特性、水气两相流渗透特性试验，揭示了结构面水气两相渗流的非线性、非均匀性以及耦合效应，建立考虑变形条件下结构面水气两相毛细压力演化模型以及相对渗透系数演化模型；基于雾化区边坡结构面的统计和模拟，建立雾化区边坡离散裂隙网络模型，提出了基于裂隙网络模型的高边坡非饱和渗流数值分析方法和坡面产流分析方法，实现了复杂裂隙岩体边坡雾化降雨入渗过程模拟。提出了考虑暂态水压力作用下多面体块体稳定性严格分析方法，解决了雾化区边坡稳定性评价难题。采用Hillerborg粘性裂纹模型模拟雾化降雨条件下，裂缝尖端水力耦合扩展破坏过程。通过空间域离散和时间域差分，建立裂隙网络水气两相渗流-变形耦合DDA数值计算格式，研制了描述滑坡启动、滑体破碎及滑坡运动全过程的DDA数值模拟方法。该计算程序能有效揭示泄洪雾化作用下边坡渐进破裂机制、破坏部位及破坏范围，为雾化区边坡稳定性评估和加固支护提供依据。