澜沧江苗尾水电站蓄水对倾倒变形边坡稳定性的影响研究

云南省澜沧江苗尾水电站倾倒变形岩石发育程度较低,距上次勘测评估地质条件已过十余年,但在水库蓄水下,水下的岩体变形破坏,对上部极强倾倒变形岩体的稳定性有较大影响。为了解其影响规律,该文结合已知的勘察结果,采用变形检测手段,以代表性倾倒变形岩体为基准,研究蓄水过程中对变形倾倒岩体累计变形量及相关的稳定性评价。从调查成果分析,距坝址58 km以外的倾倒变形体,前缘高于正常蓄水位,水库蓄水对其稳定无影响;距坝址33~58 km段的倾倒变形体,前缘高程在1390~1400 m,水库蓄水局部可能崩滑;距坝址33 km以内的倾倒变形体,蓄水后稳定性较差,可能出现较大范围的倾倒型崩塌,或局部滑移。

The development degree of the dumping deformed rock of the Miaowei Hydropower Station on the Lancang River in Yunnan Province is relatively low,and it has been more than ten years since the last survey and evaluation of geological conditions,but under the impoundment of the reservoir,the deformation and destruction of the underwater rock mass has a great influence on the stability of the upper extremely strong toppling deformed rock mass.In order to understand its influence law,based on the known investigation results,this paper studies the cumulative deformation and related stability evaluation of the deformed rock mass in the process of water storage by means of deformation detection and based on the representative dumping deformation rock mass.According to the analysis of the investigation results,the leading edge of the dumping deformation body outside the 58 km of the dam site is higher than the normal water level,and the storage of the reservoir has no effect on its stability;the elevation of the leading edge of the dumping deformation body of the 33~58 km section from the dam site is 1390~1400 m,and the local storage of the reservoir may collapse;the stability of the toppling deformation body within the 33 km of the dam site is poor after impoundment,and a large range of toppling collapse or local slip may occur.