Deformation characteristics and evolution simulation of the Maliulin landslide in the Three Gorges Reservoir area

The deformation characteristics of reservoir landslides are more complicated under the combined effect of water level fluctuation and rainfall. Taking the Maliulin landslide in the Three Gorges Reservoir area as a case study, this paper studies the deformation and evolution characteristics of the landslide according to field investigation, drilling records, deep displacement monitoring and deformation simulation. The results indicate that a secondary shallow sliding surface is detected between clay layer and rock-block layer, which controls its current activities. This phenomenon is mainly caused by the differences of landslide material composition. The S_i (S_f) parameters shows that the sliding zone of the Maliulin landslide has not been totally destroyed and the landslide keeps creep deformation at present. The reservoir water level fluctuation can be divided into six periods according to its annul variation. The landslide keeps stable during water level slow drawdown period but deforms intensely during the periods of rapid drawdown and low water level. During the periods of reservoir water level rapid rise, slow rise and high water level, the landslide has mere deformation. It should be noted that the direct effect of rainfall and its indirect effect through reservoir water level fluctuation leads to intense deformation and annual minimum factor of safety for the landslide. More early warning work can be implemented for the Maliulin landslide during the period of low water level.