Analysis On Settlement And Dynamic Response Of Track Structure When Bridge And Culvert Traversing Under Existing Railway

With the rapid development of traffic construction, more grade crossings of the railway and road needed to be changed to interchange construction. When traversing under existing railway, more and more framework bridge are selected as the type of bridge structures, the main reason is that this construction method can adopt jacking method and does not interrupt railway operation. Jacking construction inevitably cause disturbance of surrounding soil. It correspondingly affects the running safety of the operating railway line. According to this case, this paper investigates the influence of railway line when traversing through it.A three-dimensional finite element railway-subgrade model is established by using Ansys soft. On the basis of the theory of statics, this paper first analyzes the deformation of railway track structure and reinforcement system. By modeling four types of differences of excavation steps (0.75m, 1.5m, 2.25m and 3.0m), some results can be obtained, such as the maximum deformation of railway track structure and reinforcement system. From these calculation results, settlement regularities of railway track structure and reinforcement system are concluded.Finite element wheel-rail interaction model is established. The influences of the vertical dynamic loads are determined. Under the effect of train-induced dynamic load, dynamic characteristics of railway track structure and reinforcement system are analyzed.Through comparing of the vibration displacements and accelerations of railway track structure and reinforcement system under different velocities, this paper draws the regulation of the dynamic response of the railway line. Overall, with the speed of the train increases, the vertical vibration displacements and accelerations of the rail are enhanced. the displacements of the rail and the longitudinal beam increase relatively slow.