Dynamic Characteristics And Stability Prediction Of The Typical Landslide In The Shennong River Downstream Of The Three Gorges Reservoir

Landslides around the Three Gorges Reservoir,including the newborn ones and reactivated ones,are generally induced by the heavy rainfall and/or reservoir water level changing events.Particularly,the pre-existing landslides are likely to be reactivated by the annual changes of the reservoir water level,especially the Wujiayuanzi(WJYZ),Tianjialiangzi(TJLZ)and Huangjialiangzi(HJLZ)slides in the Shennong River downstream.In this paper,on the basis of full knowledge according to the Shennong River downstream typical landslide structure,geotechnical properties and combination with the actual deformation and professional monitoring data,key research of landslide deformation characteristics of space and time and the relationship between the rainfall and reservoir water level fluctuation.With the Landslides numerical model established,we can analysis the Landslides seepage field under the condition of water level fluctuation and heavy rain.And coupled with stability and deformation damage calculation,prediction of landslide stability and deformation trend.Through the above research get the following results:(1)The three landslides are stable at present,the WJYZ landslide stability is poorer.Monitoring displacement locus shows only the WJYZ landslide sliding direction is close to the main sliding direction and the law is clear.And the central monitoring value is bigger.Monitoring data reflect the water level fluctuation and rainfall had a greater influence to WJYZ landslide than the other two landslides.(2)In the steady state conditions,three landslides underground water level are flat,affected by the leading edge and the buoyancy,the WJYZ landslide's stability coefficient in the 145 m reservoir level is higher than 175 m,and the other two landslide are on the other hand.(3)In the water down/up conditions,there are hysteresis with the three landslides,and with the increase of the water level drop /rising,the hysteresis is obvious.The stability coefficient affected by penetration and with the water down/up increase,the stability coefficient will be smaller/bigger.HJLZ landslide's stability coefficient is influenced by water greater than the other two landslides.(4)In the storm+water level drop conditions,the three landslides ground water level near the sliding zone were lifted,TJLZ and HJLZ landslide rise significantly.The water level lifted increase dynamic water pressure and make the landslide stability lower.HJLZ and TJLZ landslide's stability reduce obviously by heavy rains.(5)In the storm+145m water level conditions,the three landslides ground water levels are rising along the sliding zone.In the 3 days storm conditions ground water level is lower than 5 days.TJLZ and HJLZ landslide's stability reduced obviously affected by the heavy rain.(6)The imbalance thrust method's value slightly bigger than the M-P method,strength subtraction is similar to the M-P results.Three calculation methods under different working condition of stability coefficient change trend is consistent.(7)FLAC3D's simulation results show that the WJYZ landslide's deformation mainly appears in the middle of the sliding body and the margin,the surface displacement is greater than the displacement of deep.The operation condition of the stability coefficient of the lower,the sliding body deformation in central value and the value of the shear strain increment increases and scope,the plastic zone to expand outward.