中文摘要：

坝址区复杂的地质条件与岩体力学环境变化，直接影响坝肩岩体抗滑稳定及拱坝的安全。我国西南乌东德超高拱坝坝址区工程地质条件极为复杂。坝体载荷后，区域内地层岩性、断层构造、岩溶系统、拱座内不连续裂隙等自然地质条件，成为影响坝肩岩体稳定性的主要因素。基于可研阶段地质勘探数据、二维地质剖面和工程设计数据，采用面向对象技术、多种软件协同作业，建立自然地质条件和工程对象的几何模型。构建适用于地应力反演分析，坝体载荷、工程开挖等因素影响下坝肩稳定性分析的三维精细有限元计算模型。该三维模型最大程度地模拟了工程岩体复杂结构，为高拱坝坝肩岩体稳定性综合分析提供良好的基础。计算结果表明：河谷两侧近地表地应力带及河床深部地应力区应力水平与实际量测值接近。坝肩槽开挖完成后，右岸拱肩槽800m高程附近位移值最大达到12．9mm。两岸9个可能滑动楔块在不同荷载组合条件下有一定差异，整体上左岸坝肩稳定性强于右岸。组合地震荷载作用下，所有楔块安全系数均大幅下降，但仍具有一定的安全裕度。

英文摘要：

The complex geological conditions and rock mechanics environmental changes in the dam area directly affect the abutment stability of rock against sliding and the safety of arch dam. In Southwest China, the dam area of Wudongde ultra-high arch dam has extremely complex engineering geological conditions. After the dam is unloaded, the nature geological conditions become the main factors to affect the abutment stability, such as formation lithology, fault structures, karst system, skewback discontinuous fissures. Based on the geological exploration data, two-dimensional geological sections and engineering data of the feasibility study stage, the object-oriented technology, and a variety of collaboration software are used to establish a geometric model of the natural geological conditions and engineering objects. Finally, a three-dimensional fine finite element model which is suitable for the analysis of the abutment stability is built under the conditions of inversion analysis of ground stress, the dam load, exaction and so on. The three-dimensional fine finite element model simulates the complex structure of engineering largely, which provides a good foundation for the comprehensive analysis of the stability of high arch dam abutment rock. The results show that stress level of both the near-surface ground stress zone on both sides of the valley and deep ground stress zone of riverbed is close to the actual measured value. After the excavation of dam abutment is completed, the maximum displacement reaches 12.9 mm near the right bank of 800 m elevation of spandrel groove. There are some differences in the 9 sliding blocks under the different loading combination conditions; and the stability of the left abutment is stronger than that of the right on the whole. Under the combinations of seismic loads, all safety factors of the wedges will reduce largely; but there is still some margin of safety.