Characteristics Of Vibration Sources Of Metro In Curved Track And Its Influence On Adjacent Buildings

The rapid development of the subway has eased the current situation of urban traffic congestion,but the impact of the vibration of the subway on the surrounding environment can not be ignored.In the planning and design of subway lines,limited by urban topography,spatial layout of buildings,passenger flow and other factors,many curved tracks need to be designed.However,curved tracks are the high-frequency sections where environmental vibration diseases occur.Compared with the rectilinear orbit,the environmental vibration response of the curved tracks is more complex.Therefore,a dynamic model of vehicle-track coupling vibration and a finite element model of tunnel-stratum-building under the action of metro are established,this paper analyzes the influence law of parameters such as unbalanced curve ultrahigh value,curve radius,running speed and building foundation form on the vibration intensity,building vibration characteristics and vibration attenuation.It provides reference for actual planning and design of subway lines on curve sections.Main works are drawn as follows:（1）The dynamic model of vehicle-track coupling vibration in curved track is established,and the model is verified by the measured data of rail response during train operation.The calculated reaction force of the coupler is used as the excitation source,and the finite element model of tunnel-stratum-building under the action of metro is established.The reliability of the model is verified by measuring the vibration response data of tunnel wall in curved track during actual train operation.（2）Based on the vehicle-track coupling dynamics model,the influence of unbalanced ultrahigh value,curve radius and running speed of curved track on the response characteristics of the coupler supporting force and vibration intensity are analyzed from both time domain and frequency domain,and compared with the vibration response of rectilinear orbit.On this basis,the influence of unbalanced ultrahigh values and running speed on the maximum of vertical and lateral vibration accelerations and the maximum vibration levels of building slabs are analyzed.Research indicates: both the unbalanced ultrahigh value and the running speed have a great influence on the dynamic load of vibration source and the vibration response of the building floor;In the response of each frequency band,the vertical vibration of the dynamic load of vibration source is greatly affected by the running speed,while the lateral vibration changes significantly with the change of the unbalanced ultrahigh value,the running speed and the curve radius;In the analysis frequency band,the lateral vibration of building floor increases with the change of unbalanced state and the increase of running speed,while the vertical vibration does not change obviously.（3）The basic form of building finite element model is changed and the influence degree of the vibration response of the building by adopting the four basic forms of the building that is short of shallow foundation,short pile foundation,long pile foundation and raft foundation is compared and analyzed.Research indicates: With floors increase,the building lateral vibration decreases firstly and then increases,while the vertical vibration increases floor by floor;The vibration of the building increases in the medium and high frequency components（> 20 Hz）,while the low frequency components decrease;In general,vertical vibration is greater than lateral vibration and the column vibration is greater than the floor vibration;The descending order of vibration levels of the four working conditions is as follows: raft foundation> shallow foundation> short pile foundation> long pile foundation,while the order of lateral vibration order from large to small is as follows: shallow foundation> short pile foundation> long pile foundation> raft foundation;In general,long pile foundation is the most favorable for reducing acceleration vibration level.