西尔瓜子古滑坡新活动区成因机制及数值模拟分析

西尔瓜子古滑坡新活动区是由一个大型古滑坡堆积体局部复活而成，毛尔盖水电站水库二期蓄水位达到2085 m高程左右时，滑坡体前缘部分发生较大规模的垮塌，该滑坡若产生速滑，将威胁附近新建麻窝移民集镇和斜坡内省道贝尔隧道安全，甚至给毛尔盖水电站大坝造成影响。在查明该滑坡地质环境条件、斜坡地质结构、变形滑动现象与特征和变形滑动模式基础上，采用有限元分析软件FLAC3D，基于流固耦合分析原理，建立地质结构模型，研究了该滑坡在库水作用下的变形过程及机制，确定了该滑坡滑动的临界库水位，并利用极限平衡分析方法就稳定现状和发展趋势进行了评价预测。结果表明，滑坡进一步滑动的临界库水位在2 105 m时，滑坡整体处于失稳状态。必须采取加固措施，确保工程和人民的安全。

Analysis on Genetic Mechanism of New Active Area of Xierguazi Ancient Landslide by Numerical Simulation

The new active area of Xierguazi Ancient Landslide is formed by revival of a large ancient talus landslide. When the level in the reservoir（ Phase Ⅱ1 ） of the Maoergai Hydropower Station reaches about 2085 m in elevation, a large scale collapse arose at the front part of the Landslide, and the sliding, if happened, will endanger the newly built Mawo Town for resettlement nearby and the Beier Tunnel on the Provincial Highway in the slope, even make influence on the dam of the Station. Based on the investigation of the geological conditions of the Landslide, the geological structure of the slope, deformation and sliding phenomena and the characteristics and mode, with FEM analysis software FLAC3D and the principle of fluid- solid coupling analysis, the model of the geological structure was established to study the deformation course and mechanism of the Landslide under the action of the water in the reservoir, and then to confirm the critical water level in sliding; at the same time, by limit equilibrium method, the status quo of stability and the development trend were evaluated and predicted. The results show that the critical water level for further sliding is 2 105 m, then the whole Landslide may fail.