Abstract: Rapid drawdown of reservoir water level is adverse to landslide stability. In view of this, we propose that the reservoir water level declines intermittently. On the basis of traditional analysis of persistent drawdown of water level, we analyzed the influences of intermission and intermittent drawdown of water level on the stability of landslide by using Geo-Studio software. An accumulation landslide in Three Gorges reservoir area was taken as an example. Research results show that intermission is in favor of the dissipation of pore water pressure in the landslide; meanwhile, lag effect of groundwater level’s decrease caused by rapid drawdown of reservoir weakens and hydraulic gradient decreases; when we compare reservoir intermittent drawdown with reservoir persistent drawdown, landslide stability factor of the former is bigger, but stability factor is not in proportion with intermission; under the multistage intermittent drawdown of reservoir, stability factor has obviously improved,which is greater than 5%. Finally, in order to optimize the landslide’s stability, we should reasonably arrange reservoir drawdown and intermittent time.

Key words: intermittent drawdown of reservoir water level, accumulation landslide, pore water pressure, hydraulic gradient, landslide stability, Geo-Studio, stability factor