The Research On Track Irregularity Caused By Settlements Of The Light-rail Bridge Pier

Light rail transit as a basilic component of urban traffic, the safety of its operations is extremely important. Subject to restrictions on urban land, inevitably there will be underground works through the existing situation in transportation planning. Near the piers, rock excavation would make the pier sinking, which led track irregularity to exceed the limit, then endangers the traffic. Therefore, a finite element model was created to analysis the changes of track irregularity which the settlements of the piers caused. The main research contents are as follows:1. Studied the light-rail bridge and rail line features, a three-dimensional finite element model of ABAQUS was established for the settlement problem. In the ABAQUS model, the concrete-reinforcement separate method was used to model the concrete bridge, in which the concrete, reinforcement, prestressed reinforcement elements would be established separately. Linear Spring was used to simulate the functions of rail fastener and support in the bridge-rail system. The model of railway bridge can act as a follow-up general model for the settlement question of the railway bridge.2. On a two-span bridge model,the changes of track irregularity was analyzed under five different boundary conditions. Moreover, the impact of concrete strength, Reinforcement ratio, Prestress and Fastener stiffness on the track irregularity was also studied under the boundary condition of UY. The law of changes of the track irregularity which the five different boundary conditions cause was proposed.3. In order to solve the problems encountered during the construction at the Xunlimen Station in Wuhan, this paper mainly presents the impact of three combinations of multiple-displacement boundary conditions on the track irregularity. At the same time, the value and type of the displacement which make the track irregularity tolerances reach the Limits was also proposed.