Abstract: In accordance with theories of unsaturated flow and shear strength, limit equilibrium method was employed to analyze the stability of landslide in different conditions different raising and falling rates of water level, different rainfall intensities, and combined action of water level fluctuation and rainfall infiltration. Fujiapingzi landslide on the Jinsha river was taken as an example. The calculation results show that when the water level raises faster, the growth rate of landslide’s safety factor increases; the effect of water level drawdown velocity is generally parabolic, which means that the safety factor reduces firstly and then increases. There is a critical water level at each drawdown velocity. When rainfall intensity increases, the stability of landslide worsens. With the raise of water level, the effect of rainfall on safety factor decreases. By analyzing the most unfavorable combination of reservoir water lever drawdown and rainfall infiltration in terms of time, we found that the rainfall acting in the last period is more beneficial than that acting in the initial period. The variation of safety factor of this high and steep landslide is small in all the above conditions.

Key words: high and steep landslide, reservoir water level fluctuation, rainfall, landslide stability