中文摘要：

随着我国水利水电工程的发展，出现了许多的大跨度、高边墙地下洞室，洞周围岩的稳定性是设计和施工过程中关注的关键问题之一：根据岩滩水电站扩建工程地下厂房洞室群的布置情况，结合洞室围岩地质条件，采用FLAC^3D程序建立了数值分析模型。对施工开挖过程进行了模拟，研究了洞室群围岩开挖后的位移场、应力场和塑性区的分布特征，揭示了应力集中部位和围岩潜在破坏部位的分布规律。分析结果表明断层切割、洞室交叉是影响洞周围岩稳定性的主要因素，未与洞室切割的岩脉对洞周围岩稳定性影响不大。最后综合评价了洞室的稳定性，得到了一些有益结论。

英文摘要：

With the development of water conservancy and hydropower engineering, many underground caverns with large span and high side wall have been excavated. The stability of their surrounding rock is the key problem in the design and construction process. Based on the underground house group layout in the expansion project of Yantan Hydro - power Station and the geological conditions of their surrounding rock, a FLAC^3D numerical analysis model is established. The process of the excavation is simulated, and the distribution character of the displacement field, stress field and plastic zone after the excavation and the distribution law of the stress concentration area and the potential damage zone of surrounding rock are studied. The analysis results indicate that fault intersection and cavern crossing are the main factors influencing the surrounding rock stability, while dikes that are not intersected with the caverns have little impact. Finally, the caverns stability is evaluated comprehensively and some useful conclusions are made.