Study On Time Prediction Analysis Method For Landslides Based On Landslide Displacements

There is an important practical significance of landslide time prediction to landslide prevention and mitigation. This thesis mainly focuses on two types of landslide, which are planar landslide and rotational landslide. Based on the landslide displacement, the analysis method of time prediction of landslide is obtained through the theoretical analysis, numerical simulation and experiments, and so on.The main research methods and conclusions are as follows:(1)The calculation methods of landslide time prediction of planar landslide and rotational landslide are proposed. It can be derived that the formula between the long-term strength parameters of planar landslide and rotational landslide and the landslide acceleration based on the limit equilibrium theory and the basic equation of dynamics, then it can be observed that the long-term strength parameters negatively related to the acceleration of landslide.(2)Based on the excavation project of Luding Dadu River Bridge Kangding shore of Yakang highway, indoor creep experiments are carried out on the undisturbed soil of the sliding zone using a specially modified shear creep test apparatus. The strength parameters are obtained which are the cohesion c∞= 10.6kPa and the internal friction angle φ∞=34.16°. Then the parameters of the Burgers can be determined by fitting. The shear modulus and viscosity of Maxwell are GI=1048kPa,η1=8.1×105kPa·min; the shear modulus and viscosity of Kelvin are G2=24.74kPa,η2=4.47×105kPa·min.(3) The relation type between acceleration of creep stage and monitoring time can be derived through data fitting by MATLAB based on the monitoring data of displacement of the Jimingsi landslide in the Three Gorges Reservoir Area and the Baishixiang landslide which is located in Beichuan, Sichuan. Then it can obtained that the time of Jimingsi landslide and the Baishixiang landslide reach the stage of accelerated creep are 408.5d and 184d respectively, the calculating results are considerably close to the time reaches the stage of accelerated failure in the actual monitoring.(4) Numerical simulation of creep using FLAC3D method is carried out to analyze the slope of Luding Dadu River Bridge Kangding shore of Yakang Highway、Jimingsi landslide and Baishixiang landslide. The rationality of the theoretical analysis and the method of numerical simulation is further confirmed by comparing the numerical simulation results with the theoretical analysis or field monitoring results.In this study, the analysis method of time prediction of landslide is obtained according to the landslide displacement. It can be used for the time prediction of the landslides and effective prevention and mitigation.