In order to clarify the stability of reservoir dams under the action of rainfall, flooding and other complex water flows, this paper takes the Shifosi channel-type reservoir as the basis, and establishes a finite element numerical analysis model of fluid-solid coupling by using SLOPE/W software. The basic unknown quantities such as infiltration line position, effective plastic strain and horizontal displacement of the reservoir dam are solved sequentially by the sequential solution method to simulate the mechanical behaviors of the reservoir dam under different water flows, so as to study the stability of the dam. The study shows that with the change from normal storage to flood, the water level of the reservoir dam body is increasing, the position of the internal dip line is elevated, the maximum plastic strain and horizontal displacement of the dam body increase, and the maximum values are all found at the foot of the dam location. The FOS for the three complex working conditions were 1.931, 1.864 and 1.842, respectively. This indicates that the stability of reservoir dams is, in descending order: normal storage > rainfall > flood.
