Free Field Vibration Caused By Traffic Operation Based On 2.5D Finite Element Method

Vibration caused by road and rail traffic is causing increasing environmental problems in urban areas,as these vibrations may affect the residents of roadside/rail-side buildings and affect the normal operation of vibration sensitive instruments.In this paper,a 2.5D finite element model of highway and railway is established to predict the vibration response induced by road and railway traffic.In order to predict the vibrational response induced by road traffic,a two-step 2.5d FEPML method was proposed.Secondly,the road soil layer model was meshed with the 2.5D finite elements,and the absorption boundary was established with the 2.5D PML element,from which the transfer equation between the source point and the receiving point was derived.The free field response under moving load can be calculated by combining the two steps,and the reliability of the improved method is verified by comparison with 2.5d FE-BEM(2.5D finite element-boundary element method).The 2.5D FE-PML method was used to predict the corresponding road surface of HINO trucks in a certain road section in Hong Kong,and a comparative analysis was made on the experimental data of this section,which proved that the method could predict the traffic-induced vibration response.In order to predict the vibration caused by railway,the train-track-soil model is divided into three independent models: soil model,track model and train model.The train model was simplified into a 10-dof vehicle model,while the track model was idealized into an equivalent continuous model with six DOF.The contact surface between track and soil was simplified into a massless strip foundation model.The soil model was meshed with 2.5d finite elements,and the absorption boundary was established with 2.5d PML element.The dynamic load of axle is determined and the corresponding transfer equation is derived.By comparing existing field tests in the Portuguese railway network,it is proved that the train-track-soil model of 2.5D FEPML method can predict the responses of track and free field well.