Study On The Vibration Of Ground And Buildings Caused By Subway Trains

In recent years, with the rapid development of China’s economy and the accelerating process of urbanization, urban ground transportation has been increasingly saturated. Metro as a mode of transport using underground space is playing an increasingly important role in relieving the traffic pressure and facilitating aspect of people’s daily travel. But with the subway developing, subway vibration problems are becoming increasingly prominent, and it has become one of the seven pollutions in the world. Therefore it is very necessary to study the ground and building vibration caused by the operation of the subway. In this paper, ANSYS finite element software is used to establish a finite element model of tunnel- soil-building to study the vibration problem of ground and buildings caused by subway trains. The main contents are as follows:Firstly, the basic conceptions of the finite element method is introduced and it explores the correlation parameter method of finite element model comprising determining the train load, calculating the dynamic soil parameters, model size, mesh size and artificial boundary conditions, and so on.Secondly, two-dimensional and three-dimensional finite element model are built,and the excitation function is used to simulate the train load.And the full transient analysis is used to analyze the vibration response of the ground and buildings under the different speed of the train and depth of tunnel,based on which the vibration laws of the ground and buildings are summarized and the significant factors affecting environmental vibration caused by the train are obtained.Thirdly,this paper compares the results of two-dimensional and three-dimensional models and analyzes the similaruties and differences of the numerical simulation of the two models.The result shows that the vertical ground vibration caused by the subway decreases as the increase of the distance from the subway centerline except that there exist a vibration enlarged area.And the vibration intensity at the same point decreases as the reduce of the train speed.The building shows the trend of overall vibration.And tunnel depth can significantly affect the vibration strength of the surface ground.The simulation results of two-dimensional are larger than three-dimensional,but the overall attenuation trend is consistent with each other.