库水位对库岸边坡稳定性的影响

Study on Influence of Water Impounding to the Reservoir Landslide

水库蓄水改变了库区两岸的水文地质条件,造成库岸边坡稳定性也发生较大变化。以甘肃省九甸峡水库燕子坪28#滑坡为例,通过分析滑坡监测点位移变化,定量化分析水库蓄水对库岸边坡稳定性的影响规律。基于监测点位移的差别将滑坡分为Ⅰ、Ⅱ_1、Ⅱ_2和Ⅲ四个区,分析结果表明:1蓄水位较低的监测期滑坡较为稳定,整个滑坡变形遵循原有属性;2蓄水过程中滑坡具有明显的分块、分区和季节性变化特征,其稳定性呈稳定—较不稳定—稳定的变化趋势;3蓄水位在一定范围内,库水位下降有利于库岸边坡的稳定;4蓄水过程中燕子坪滑坡属于复活古滑坡。

After water impounding,hydrogeological conditions on both sides of the reservoir area is affected in a large degree which leads tothe stability of landslide being changed. Taking Yanziping No.28 landslide of Jiudianxia Reservoir in Gansu Province as an example,usingGPS to monitoring the deformation of the landslide in near-real-time and long-term and according to the analysis of the landslide of JiudianxiaReservoir on external deformation,the law of influence of reservoir water level to the landslide stability has been quantitatively analyzed.Based on the different deformation of the monitoring sites in landslide,the landslide was divided into four areas（Ⅰ,Ⅱ_1,Ⅱ_2 and Ⅲ area）.The results show that in the low water level monitoring period,the landslide deformation follows its original attributes with being a steadystate;the landslide deformation has a smaller-larger-stable deformation characteristics;it owns obvious partition,partition and seasonalvariation characteristics,including the biggest displacement;it is adverse for the stability of the landslide when the reservoir fall during thephase of 115-130 m;the Yanziping landslide belongs to the ancient landslide revival during the period of reservoir impoundment.