三峡水库水位变动下的库岸滑坡稳定性评价

Stability assessment for the landslide undergoing the effects of water level fluctuation in the Three Gorges Reservoir area,China

摘要: 水库岸坡滑坡稳定性主要受库水位涨落的影响。由于库区水位变化可概化为二维非稳定流,地下水位变化可采用有限元模拟。三峡水库正常运行时的水位涨落速度在0.6～4.0m/d、高程145～175m之间变化,通过有限元法对库区的马家沟滑坡模拟表明:库水位和滑坡体内的地下水位同步升降,水力梯度很小,因此水位涨落对滑坡的影响主要是浮托力作用。在此条件下,采用Morgenstern-Price法对滑坡稳定性进行计算表明,随着水位上升,滑坡稳定性降低,水位上升到165m时,稳定性达到最小,水位再上升则稳定性增大,当滑坡完全淹没在水下时的稳定性高于未被淹没的情况,滑坡最终的稳定性按最小稳定系数评价。

Abstract: The Majiagou landslide,as a case for study,is located on the left side of the Zhaxihe River,a tributary of the Yangtze River.After the water level of the Three Gorges Reservoir rose from 95m to 135m in June 2003,the Majiagou landslide occurred including a 20m long,3～5cm wide(locally 10cm wide) fissure at its back that occurred in a time-frame of 3 months.The implication is that the reservoir impounding reactivated the landslide.The slide mass of the Majiagou landslide is composed of a thin layer...