Due to rainfall and water-level fluctuation

deformation increases on a large number of landslides

which create severe geologic hazards problems in Three Gorges reservoir area. The study of influence factors

deformation evolution rules and instability conditions of reservoir bank landslide is conducted by physical modeling test. Taking Huangtupo riverside slump-mass No.I as an example

a typical reservoir landslide in the Three Gorges Reservoir area

a series of model tests of landslide was carried out by taking into account the induced factors such as water level fluctuation

rainfall and their combination. Test results show that the deformation mainly locates at the front edge of the model slope during water level fluctuation. The deformation acceleration stage occurs during the decline of water level

and the deformation rate is directly proportional to the water level decline rate

while deformation is relatively small with rising water level. Therefore

the landslide of Huangtupo riverside slump-mass No.I is a dynamic-water-pressure type. The model deformation shows obvious spatial and temporal zoning under rainfall. The deformation mainly occurs when the shallow part of the model is saturated. Spatially

large deformation is generated at the front and trailing edge of the model slope. The model slope fails from local slip failure to the leading edge failure under heavy rainfall and decline of water level

showing a progressive retrogressive mode. Finally

the experiment reveals that abnormal fluctuations of pore water pressure and earth pressure occur at the near-sliding stage

which can provide some reference for landslide warning and prediction.