Stability Trend Prediction Of The Typical Landslides In The Xingshan Section Of The Three Gorges Reservoir

Landslides in the Three Gorges Reservoir area,including the newborn and the reactivated,are generally affected by rainfall and reservoir water level fluctuation.With the annually periodic variation of water level of the Three Gorges Reservoir,the stability condition of reactivated landslides will also change.Xingshan segment of the Reservoir is located in the middle and low reaches of Xiangxi river,a tributary of Yangtze.In this area,the physical properties of rock strata are so weak that landslides happens easily;Qiaotou(QT),Wuzhuangbuganjuyuan(WZBGJY)and Shuiwenzhan(SWZ)slides are the three typical landslides in this area.This thesis takes these three typical landslides as the research objects and analyzes the relationship between the spatial and temporal characteristics of landslide deformation and water level fluctuation and the amount of rainfall with the use of finite element software Geo-studio and finite difference software Flac3 D.Results are as follows:(1)Those three landslides do not show obvious damage at present and the current situation of the landslide is stable.According to the monitoring data,the sliding direction of WZBGJY landslide had no clearly regularity changing.(2)In the declining or rising conditions,the groundwater levels of those three landslides exist lagged phenomenon which is more obvious with the increasing rising or falling rate of the reservoir water level.The stability coefficients of QT and WZBGJY landslides decrease with the increasing falling rate and increase with the increasing rising rate.The stability coefficient of SWZ landslides increase with the increasing falling rate and decrease with the increasing rising rate.(3)In the heavy rainfall conditions,ground water levels of these three landslides near the sliding zone were lifted,especially that of WZBGJY landslide rose most significantly.The water level lifted increase dynamic water pressure and make the landslide stability lower.WZBGJY landslide's stability reduces obviously by heavy rains.(4)The minimum stability factors of QT and WZBGJY landslides were in the condition of stormy rain and the 3.0m/d of declining water level and the figures are 1.052?1.083.The minimum stability factor of SWZ landslide is in the 175 m water level and the figure is 1.061.According to the data,it predicts that the stability factor of landslides is basically stable in all conditions.In part of the WZBGJY and SWZ landslides are in good stability condition and all the figures are greater than 1.05.The stability on the light middle part of QT landslide is not quite good in the condition of storm rain.(5)FLAC3D's simulation results show that the QT landslide's deformation mainly appears in the middle of the sliding body and rear edge,the surface displacement is greater than the displacement of deep.With the quickly falling drawdown rate of the water level,the value of the central sliding deformation and shear strain increment increases and scope,the plastic zone to expand outward,yet it is not well cut-through;the QT landslide is basically stable.