库水位变化条件下滑坡稳定性研究——以雅砻江某水电站虎山滩滑坡为例

Research on landslide stability under water level fluctuation of reservoir:case of Hushantan landslide of a hydropower station on Yalong River

虎山滩滑坡位于雅砻江某水电站上游,滑坡体大,一旦失稳,将严重影响水库安全。根据非饱和土的渗流和抗剪强度理论,利用有限元分析软件Geo-studio,对库水位下降和降雨条件下滑坡的渗流场进行了模拟研究。结果表明:滑坡的稳定受库水位变化的影响较为明显,库水位上升时,稳定系数降低;库水位下降时,稳定系数升高;稳定系数最低值为1.22,即库水位变化时滑坡可保持稳定状态。为确保安全,建议对滑坡采取监控措施。

Hushantan landslide is located at the upstream of a hydropower station on Yalong River with a total volume of 22 million m3. The water level rises by 80 m after impoundment of the reservoir, once the landslide losses stability, the reservoir safety will be threaten seriously. According to the theories of unsaturated soil seepage and shearing strength and using finite ele- ment analysis software Geo - studio, the seepage field in the landslide was simulated under the condition of reservoir water level drop and rainfall. The results show that the landslide stability is obviously influenced by the reservoir water level variation, the stability coefficient reduces when the reservoir water level rises and increases when the reservoir water level drops, the minimum stability coefficient is 1.22, which means that the landslide can maintain stable when the reservoir water level varies. In order to ensure the reservoir safety, it is suggested that the monitoring measures should be taken to provide a support for landslide preven- tion and control.