古水水电站争岗堆积体滑坡复活条件分析

Landslide reactivation of Zhenggang deposit talus at Gushui Hydropower Station

针对古水水电站争岗堆积体目前处于稳定状态,在降雨、地震等不利条件下可能发生滑坡以至于威胁下游洞室群出口安全的问题,在地质勘查的基础上,选取典型剖面进行地质特性分析,并建立合理的颗粒离散元模型,进行不同工况量变条件下的滑坡复活数值模拟。结果表明:滑面倾角急剧增大和断层发育处容易产生裂隙,且影响着滑坡启滑位置;滑面平均作用3 m水头时堆积体出现蠕滑,5 m水头时三期滑坡复活;当地震强度达到0.3g时,一级平台堆积体开始滑动,形成三期滑坡。

Zhenggang deposit talus at Gushui Hydropower Station is in a stable state at present. However,it may become unstable under conditions of rain or earthquakes,which may lead to landslides and even threaten the safety of cavern exits downstream. In order to solve this problem,a typical geological profile was chosen for geological characteristic analysis. Then,a granular discrete element model was built for numerical simulation of landslide reactivation in different cases. The results show that cracks easily occur near the position where the dip angle of the slip surface increases sharply or a fault develops,which also affects the initial landslide position. When the water pressure of three meters is loaded on the slip surface,the deposit talus starts to creep,and when the water pressure reaches five meters,a third-stage landslide may become active aqain. When the seismic strength reaches 0. 3g,the deposit talus on the first platform begins to slide,and a third-stage landslide is generated.