水工高陡岩质边坡微震损伤效应及其失稳机理研究

The issue on stability of high steep rock slopes subjected with excavation disturbance is increasingly highlighted, with the continuous exploitation and construction of some large-scale energy source projects such as the West-East power transmission and the South-North water transfer project. The right bank slope of Dagangshan hydropower station along Dadu River in Sichuan province is regarded as the research background in this study. The natural height of the rock slope is more than 600 m and the excavation height is over 400 m. Different approaches such as on-site microseismic monitoring, theoretical analysis and numerical simulation are adopted to analyze the stability of the rock slope subjected with excavation disturbance. The macroscopical potential failure modes and mechanism of slope induced by the initiation, growth, extension, coalescence and interaction of microfractures inside rockmass subjected with continuous excavation, consolidation grouting, reinforcement measures, impoundment of the dam and dramatic rise and decline of water level etc are in-depth analyzed,as well as some special measures. Stability assessment mechanism and hazard forecasting design procedures of high steep rock slope in hydropower stations in the west of China subjected with excavation disturbance are thus put forward, which provide important theoretical significance and engineering application value on the safe operation of high rock slope in large-scale hydroelectric projects in western China.

随着我国西电东送、南水北调等大型能源工程的不断开发建设，开挖扰动作用下的高陡岩质边坡稳定性问题将日益突出。本课题以正在施工中的四川省大渡河大岗山水电站右岸边坡为研究背景，该边坡自然高度在600 m以上，开挖坡高达400 m之巨，通过对开挖扰动下岩质边坡的现场微震监测、理论分析以及数值模拟试验等手段，深入研究高陡岩质边坡在开挖、固结灌浆、加固措施和大坝蓄水及库水位骤升骤降等作用下其内部岩石微破裂萌生、发育、扩展、贯通与相互作用诱致边坡宏观的可能失稳破坏模式与机理，以及特殊的处理措施；提出一套适用于西部水电站开挖扰动作用下高陡岩质边坡稳定性评价机制与灾害预警设计方法，对于西部大型水电枢纽工程的高边坡安全运营具有重要的理论意义和工程应用价值。

本项目以西南地区大型水电工程岩质边坡为研究背景，基于“岩质边坡细观岩体微破裂聚积和演化渐进发展是边坡宏观失稳前兆”的学术思想，将岩质边坡微震活动监测与应力场数值分析相结合，通过应力场的演化来解读边坡岩体渐进破裂诱发失稳过程中的微震活动性规律，建立了考虑微震效应的三维弹性损伤演化本构模型，以岩石介质变形过程中的微破裂积累造成的力学性质弱化来反映岩石宏观变形非线性的本质特征，探讨工程扰动作用下水电高陡岩质边坡微破裂萌生、发育、演化、繁衍及相互作用对其宏观结构破坏过程中微震活动性的影响，包括边坡岩体破裂过程中的微震时空分布规律及其失稳的前兆模式，揭示了岩质边坡微震活动性、背景应力场演化与工程扰动之间的联系，提出一套适用于西南地区工程扰动作用下水工高陡岩质边坡稳定性评价机制与灾害预警设计方法。项目研究成果成功推广应用到金沙江白鹤滩水电站左岸边坡稳定性评价和大渡河猴子岩水电站地下洞室群围岩稳定性分析中，促进了西南地区水利水电工程技术的创新和发展，取得了一定的社会效应和经济效益。.项目的研究成果最终形成的研究论文被SCI收录5篇，EI收录10篇；获得中国岩石力学与工程学会科技进步一等奖1次，四川省科技进步三等奖1次；参加国际、国内学术会议12次，培养博士生2人，硕士生1人。超额完成项目的预期目标。