In order to accurately grasp the deformation and stability evolution law of Huangtupo riverside slump-mass No.I during the reservoir operation

exploration tunnel group was firstly used to expose the geological structure and spatial form of the slump-mass

a geological model of double sliding zone was established based on the exposed information. Then the dynamic groundwater seepage field could be obtained by saturated-unsaturated seepage finite element method

based on which the deformation and stability evolution process was studied. The research showed that the deformation of slump-mass mainly occurred in front of shallow landslide during the drop of the water level

and has significant traction movement characteristics. The deformation evolution law was verified by measured data of global positioning system (GPS) monitoring point. Stability of the shallow landslide was fluctuated obviously during the evolution process because of the dynamic fluctuation of groundwater seepage field’s

and its critical instability velocity of drawdown of water level is 2.0 m/d. Consequently

the overall stability of Huangtupo riverside slump-mass No.I is fine; but there still exists a possible that the front of shallow landslide may be instable locally under rainfall and reservoir water level drawdown.