Study On Subway-induced Environmental Vibration

Metro develops rapidly with its advantage of punctuality and mass conveyance,which induced notable structure vibration and ground-borne noise to nearby residents,adjacent stucture,sensitive instrumentations and historic buildings.It is of great realistic significance to proceed systematic research of ambient vibration caused by metro trains and kinds of vibration reduction measures to meet the requirements at multiple sensitive points.The theory and analyzing method about environment vibration and numerical solution of coupled wheel-track system is summed up. A dynamic model system coupled with vehicle-track-tunnel-soil is established to analyze the characteristics of vibration resource and the response of the enviroment. Contributions of vehicle and track parameter to the system and performances of different vibration attenuation have been studied roundly in this paper.The main achievements include:Numerical solution of the coupled dynamic system and whole vehicle model under the perturbation of track irregularity is obtained.The conmmon propagation and attenuation law of body and surface wave in saturated soil is disscused.The three-dimensional tunnel-soil interaction problem is solved to evaluate the nolinear response to the moving vehicle dynamic loads of the system with a subdomain formulation.Considering the track irregularity and the Hertz nolinear contact,artificial boundary is imported to simulate the semi-infinite domain.Complete finite element model of vehicle-track-tunnel-soil is established to calculate the vibration load spectrum in the vehicle-track system,stress and acceleration of a observation point.Train,track and ground-borne vibration responses under conditions of different fastener stiffness are provided to analyze the influence of track parameters. Ground-borne vibration responses are simulated and analyzed form viewpoints of time and frequency domain to obtain the progagation regulation.The vibraiton of tunnel and buildings are analyzed when subway runing under different speeds,the secondary structural noise in the buildings is predicted.Performances of ordinary fastenings,rail vibration absorber fastening and the steel spring floating slab track is evaluated by comparing the vertical vibration acceleration levels of rails,track beds and tunnel walls.An orthogonal test with a table under4factors and3levels is designed to analyze different influence parameters on the steel spring floating slab track and the train-induced ground vibration.