Numerical Simulation Of Dynamic Process Of Typical Landslide In Mountain Railway Based On Seismic Signal Analysis

Due to the complex geological environment in mountainous areas of China,landslides have become an important potential danger in the construction and operation of railways.It is particularly important to study the dynamic process of landslide for risk early warning and emergency prevention.In this study,a numerical simulation method of landslide dynamic process based on seismic signal analysis is proposed,and the results of seismic signal analysis are used as the verification indicator for the input parameters of numerical simulation.The seismic signal of two large-scale landslides,say,Yigong landslide in 2000 and Baige landslide in 2018,along Sichuan-Tibet Railway is first analyzed.Numerical simulation using Discrete Element Method is then conducted to reconstruct the whole process of landslides.In summary,the contents and conclusions of this research can be summarized as follows:1.The characteristics of the seismic signals generated by the landslide are: amplitude sudden increase,“spindle shape” spectrum shape and slow attenuation of the signal tail.Specifically,the envelope shapes of time-domain curves and time-frequency spectra are usually “double/single spindle” and “double/single peak”.Taking Xinmo landslide in 2017 and Shuicheng landslide in 2019 as examples,the dynamic process of landslide was preliminarily reconstructed based on the analysis of seismic signals characteristics.2.Due to the complementary advantages of the seismic signal analysis and numerical simulation methods,a numerical simulation method system of landslide dynamic process based on seismic signal analysis is proposed.When the distance between the station and landslide is more than 200 km,the envelope of signal and the accumulation range are used as the criteria for numerical simulation.When the distance is less than 200 km,the average velocity,displacement inverted by seismic signal combine with accumulation feature are used as the verification indicator for the input parameters of numerical simulation.3.In view of the two different situations in the proposed method system,Yigong landslide in 2000 and Baige landslide in 2008 are taken as case study to reconstruct the dynamic process of landslide.The results show that dynamic process of Yigong landslide can be divided into fast sliding stage channel blocking stage and accumulation stage.The accumulation characteristics are consistent with the actual situation,critical success index is 0.78.The simulated landslide duration is 294 s close to the signal duration of 300 s.The curve shape of Savage number versus time is consistent with the envelope shape of signal in time domain.Dimensional analysis shows that the change of landslide topography has a significant impact on the collision and shear behavior of particle flow.4.The result of Baige landslide show that the landslide process can be divided into sliding stage,accelerating stage and diffusion accumulation stage.The accumulation characteristic of landslide simulation is basically consistent with the actual situation,CSI is 0.65,maximum thickness 92 m.The average displacement curve from simulation and seismic signal analysis are in good agreement throughout the dynamic process.The average velocity is basically consistent in the trend,and the key points of the curve change are basically corresponding.Specifically,the simulation results are in good agreement with the seismic signal analysis results in the sliding stage,followed by the accumulation stage,and slightly worse in the acceleration stage.