关键词: 鸡扒子滑坡, 稳定性评价, Sarma法, 敏感性分析

Abstract: Several landslide events have successively occurred at Baota slope area of Yunyang County, Sichuan Province, among which the Jipazi landslide is the latest one. The Jipazi landslide represents partial revival of an old landslide. The total volume of the sliding mass is up to 1.5?10⁷m³ or more, of which about 2.3?10⁵m³ were detached from the slide channel and slided down below the flood level of the Yangtze River, causing a serious danger to the navigation on this river segment and enormous economic losses. Once the Three-Gorges Reservoir stores water, the water level of the Yangtze River will be much higher than the current level. As a result, new landslide may revive on the old one. Based on the research on the geometry, material component, structural and hydrogeologic features of the sliding mass, it is preliminarily concluded that the Jipazi landslide was caused by the increasing of pore pressure in the sliding mass due to excessive rainfall infiltration and impeded drainage during the storm. In the light of the limit equilibrium theory, a program of Sarma method is designed to evaluate the stability of the Jipazi sliding mass after the Three-Gorges reservoir storing water. The result shows that the critical value of the slope stability is that the water level of the Yangtze River reaches 145m high and the drainage rate of the slope is 50%. The dynamic sensitivity analyses of the factors affecting slope stability are carried out through adjusting the values of some affecting parameters of slope stability. The results show that the rainfall infiltration, the water level of the Yangtze River after the Three-Gorges reservoir storing water and the drainage rate of sliding mass are the crucial causes affecting stability of the Jipazi landslide. Little rainfall infiltration, low water level of the Yangtze River and unimpeded drainage in the sliding mass will enhance the stability of the slope. Therefore, corresponding prevention and control measures must be taken before the Three-Gorges reservoir stores water.

Key words: Jipazi Landslide, stability evaluation, Sarma method, sensitivity analysis