Numerical analysis of slope stability influenced by varying water conditions in the reservoir area of the Three Gorges, China

Landslide disasters have become one of the main problems after the Three Gorges impounded. Scholars from all over the world have paid much more attention to the stability of slopes in the reservoir area. Water has been regarded as the main factor which may directly trigger landslides, while the change of water conditions can't be avoided in the slopes in the Three Gorges. The water conditions mentioned in this paper refer to reservoir water level and water table in slope body. They will inevitably deteriorate the slope stability in some degree. The paper aims to investigate their influence on slope stability. A promising numerical analysis technique by shear strength reduction based on finite differential method is introduced here to deal with such a problem. According to the results from a real landslide in the Three Gorges, the curve between the factor of safety and the change of water level is parabolic: the slope stability will be reduced at the first stage of raising reservoir water level and then the factor of safety will be increased after that. However, the landslide will always greatly suffer from the instability when the reservoir water level drops down and the water table rises. It will provide a direct proof for the landslide prevention and remedial designs in this case.