Abstract:

An external power leading to significant landslide displacement and own geological characteristics of landslide are usually ignored in most researches based on mathematical models or methods, so deformation prediction of accumulative landslides is of low accuracy and reliability. Taking typical accumulative Hefeng landslide in the Three Gorges Reservoir as an example, four major controlling factors are constituted scientifically to establish the geological model of the landslide. A numerical-mechanical model was established considering emphatically the external reservoir water effect. And then comparing the data of field monitoring in strong deformation zone and the displacement track points in numerical model, the equivalent relation between the actual time and the step in FLAC3D model is obtained , and characteristics of water level fluctuations under different step is determined based on timestep relation and design operation water level curves of Three Gorges Reservoir. Then the deformation trends of landslide was forecast for next hydrological year by the extension of the step. The prediction method not only considers the based engineering geological model of landslide，but also considers the effects of groundwater, and it overcomes the shortage of pure mathematical prediction methods.

Key words: landslides, accumulative landslide, deformation prediction, engineering geological model, groundwater effects