Vibration Responses Of Ground Environment Along Urban Rail

With the development of urbanization.the population density of large and medium-sized cities is increasing year by year.Traffic jams are becoming more and more serious.As an important way to relieve the pressure of urban traffic,China's urban rail transit system is widely constructed because of its characteristics of small pollution,high speed,large traffic volume and safety.However,while people enjoy the convenience of urban rail train,the vibration of the ground along the line caused by the train operation has a significant impact on people's daily life and work environment.Based on the field measurement of a certain section of Beijing Metro Line 13,this paper applies the theory of high-speed railway to urban rail transit.An environmental vibration analysis model is established by the semi-analytical finite element method.The model is composed of the vibration source model built by the analytical method and the site model built by the finite element method.It can be used to predict and evaluate the vibration caused by the urban rail train.The main contents of this paper include:(1)According to the basic vehicle dynamics equations,a new train-track-foundation interaction model is established by using the improved track-foundation interaction model.Fourier integral transform is used to solve the equation of the model,and many factors affecting the vibration in the model are considered,such as track irregularity,train velocity,passenger capacity and train formation,etc.(2)After the excitation force of vibration source is calculated in the analytical model,it is applied to the track-foundation model established by ABAQUS finite element analysis software.This model used the infinite element boundary condition,which can attenuate the vibration to infinity,increase the accuracy of model calculation,and then calculate the vibration response of the site.(3)The vibration test record of the site around the urban rail line in a section of Beijing Metro Line 13 is verified by the semi-analytical finite element model established in this paper,which proves the validity of the model.This method has a certain practical value for evaluating the environmental vibration of existing lines and predicting the environmental vibration of new lines.