Non-Stationary Random Vibration Analysis And Site Response Spectrum Study Of High-Speed Train-Track-Foundation Soil

In recent years,the problem of environmental vibration caused by high-speed railway has become increasingly prominent.Therefore,how to effectively calculate the statistical characteristics of soil vibration and evaluate the vibration environment is particularly important.The dynamic interactions between vehicles and surrounding structures are essentially random.In the present thesis,based on the stochastic vibration theory,the symplectic methods,the wave spectrum element method,the pseudo excitation method for random vibration,and the thin layer method,are adopted into the vibration analysis of the coupled system,The statistical characteristics and field response spectrum of foundation soil under high-speed trains are calculated and analyzed.The main contents include:(1)Vertical random vibration analysis of vehicle-track coupling systemsTrack structure is a kind of typical infinite periodic structure.Establishment of spectral-symplectic motion equation for ballasted orbits by combining symplectic method and the wave spectral element method.Converting random track irregularity into harmonic excitation force by pseudo-excitation method,calculate the virtual response of the vehicle-track coupling system,and then,the time-varying power spectrum and standard deviation of vibration response are obtained.Finally,the correctness of the model is verified in numerical examples,the influence of the characteristics of foundation soil on the random response of the coupled system is also discussed.In the numerical example,the statistical characteristics of surface vibration response under the action of single wheel-rail force or wheel-rail force load column are analyzed.(2)High-speed trains induced non-stationary random wave propagation in layered soil mediaRandom vibrations of the orbit caused by train operation will propagate outward,impact on nearby venues.Wheel-rail force load is random,so the vibration response on the surface near the track is a non-stationary random process.Establishment of orbit-foundation Soil coupling analysis model by Thin Layer Method.Then use the virtual excitation method to solve the statistical characteristics of the vibration response of the foundation soil.(3)Analysis of vibration environment threshold of high speed trainThe site vibration response spectrum is proposed,and compare it to the selected limit.The threshold for the excellent period and distance from the center of the track when the vibration limit is reached without any vibration isolation measures is obtained,provide a theoretical reference for the actual project site selection.