Analysis Of Deformation Mechanism And Stability Prediction Assessment Of Zhujiadian Landslide In The Three Gorges Reservoir Area,Badong County

In this paper,the Zhujiadian Landslide in Badong County,Enshi Prefecture,is selected as the research object.The regional geological background and boundary characteristics of the landslide are analyzed.Based on the characteristics and influencing factors of landslide deformation,the numerical model of the landslide deformation and failure process is established,which reproduces the process of landslide deformation and failure.By summarizing and analyzing the landslide deformation characteristics and numerical calculation results,the mechanism of landslide deformation(failure)is clarified.The spatial evolution process of landslide deformation and failure,the stability of landslide,which is under the condition of superimposed rainstorm and the sudden rise and fall of reservoir water level,are predicted.The following conclusions and results are obtained in this process.1)The dense tectonic fracture belt,in the Badong area,leads Zhujiadian Landslide landslide to deforme and destroy.The structural area is located in the Sichuan-Eagle fold mountainous area,which is intersected by multiple structural systems,forming a dense structural fracture zone,which is an unstable perimeter of the landslide.2)Tthe Zhujiadian landslide is concave and convex,and the front edge slope body is eroded by the Yangtze River for many years,that is a temporary surface,which makes the landslide easy to slip.3)This landslide surface is covered by a wide range of rock-sanded blocks of rockfills,which are loose and have a low content of gravel.Gravel silty clay is the main material component of the slip zone.Under the long-term alternating wet and dry cycle,the material is in a saturated-unsaturated-saturated state for a long time,which makes the landslide easily deforme.4)These data are analyzed,which are macro deformation data,GPS surface monitoring data and deep displacement monitoring results.Through the analysis,it obtains deformation-reservoir water(rainfall)response law.It shows that the deformation mainly occurs in the shallow surface layer and goes out of the isovelocity deformation stage,which is mainly related to the decline of reservoir water level and rainfall,and greatly influenced by the underwater velocity of the reservoir.5)The software ABAQUS was used to simulate the deformation and failure process of this landslide.The seepage field,stress field,displacement field and plastic zone are analyzed.The results show that the decline of reservoir water and heavy rain are the main reasons for landslide slippage.6)The dynamic hydraulic pressure destroys the landslide.(1)In the rising stage of the reservoir water level,the pressure is directed to the inside,which acts as a “back pressure” and is beneficial to the stability of the landslide.(2)In the stage of the reservoir water level decline,the pressure,in the slope,cannot catch up the rate of decline of the reservoir water level,so that the pressure is directed to the outside of the slope,which is unfavorable to the stability of the slope.7)The Zhujiadian Landslide is currently in the stage of creep deformation.According to the distribution law of deformation in space,the process of traction-pull deformation is predicted,and the stability state is predicted,which is combined with,many times,the rapid decline of reservoir water levels and heavy rainfall.