Xinli Hu* (胡新丽), Huiming Tang (唐辉明), Changdong Li (李长冬)Faculty of Engineering, China University of Geosciences, Wuhan 430074, China Renxian Sun (孙仁先)Hubei Center of Geological Hazard Control, Wuhan 430034, China
ABSTRACT: After the normal operation of the Three Gorges Reservoir, the water level of the reservoir will fluctuate periodically. Water level fluctuation will soften the rock and soil on the banks, induceunderground water fluctuation and decrease the shear strength of rock soil on the banks, and in turnaffect the landslide stability. The Huangtupo (黄土坡) landslide is a typical large and complex landslidein the Three Gorges Reservoir region. In particular, the stability of its riverside slumping mass has agreat stake. On the basis of the analysis of engineering geological condition and formation mechanismof the Huangtupo landslide, the authors established the 2D finite element model of riverside slumpingmass II# and selected proper mechanical parameters of the rock. With the GeoStudio software, according to the reservoir running curve, the simulation on coupling effect of seepage field and stress fieldwas conducted in 7 different modes in a year. The results showed that: ① Huangtupo landslide is alarge and complex landslide composed of multiple slumping masses, which occurred at different phases.Before reservoir impoundment, it was stable; ② it is quite difficult for riverside slumping mass I# andII# to slide as a whole; ③ the stability coefficient of riverside slumping mass II# changes with the reservoir water level fluctuations. The minimum stability coefficient occurs 48 days after the water levelstarts to fall and the moment when the water level falls by 11.9 m. Landslide monitoring result is consistent with the numerical simulation result, which shows that although the reservoir water level fluctuation will affect the foreside stability of the landslide and induce gradual damage, the riversideslumping mass II# is stable as a whole.
KEY WORDS: operating condition, Three Gorges Reservoir, riverside slumping mass II#, Huangtupolandslide, finite element method, landslide stability.