金沙江白鹤滩水电站坝区左岸边坡变形特征及机制分析

左岸河谷边坡的稳定问题是白鹤滩水电站重要的工程地质问题之一，在地质历史过程中，随着河谷下切，岸坡不同部位不同高程的岩体均产生不同程度的卸荷变形，研究这些变形特征及变形机制对于从宏观上定性把握左岸边坡的稳定性至关重要。根据勘察成果初步分析，左岸河谷边坡变形受缓倾角错动带以及NW向断层控制明显，具体地，卸荷裂隙的空间分布和发育规模均与其相对这些控制性结构面的位置相关，并且表现出较强的规律性。总结这些规律并采用离散单元数值分析软件UDEC和3DEC模拟河谷下切过程中这些控制性结构面对边坡变形的控制作用，进一步印证地质上的分析成果，同时结合地质勘察与数值计算成果分析左岸边坡的变形机制。

ANALYSIS OF SLOPE DEFORMATION CHARACTERISTICS AND MECHANISM IN LEFT BANK OF BAIHETAN HYDROPOWER STATION JINSHA RIVER

This study focuses on the slope deformation characteristics and mechanism in the left bank of Baihetan hydropower station on the Jinsha River. As the unloading deformation develops with the erosion of the river in geological history，the rock mass on the slope at different elevations and localities has various deformation features. It is very important to study these features. Based on the investigation data，the deformation controlled by the slightly-inclined angle dislocation interfaces as well as the NW fault zone mainly was simulated by the distinct element numerical analysis code UDEC and 3DEC after the development mode of unloading deformation was summarized，The controlling effect of key structureal plane was illustrated during the erosion of the river，proving the geological analyses further. The slope deformation mechanism was analyzed in combination with the geological investigation and numerical calculation results。