减振CRTS Ⅲ型板式无砟轨道路隧过渡段动力分析

Dynamic Performances of CRTS Ⅲ Prefabricated Slab Track with Anti-vibration Structure in Subgrade-Tunnel Transition Section

为了设置合理的过渡段长度，最大限度地减小路基与隧道之间变形差对行车安全性和舒适性的影响，基于有限元方法和车辆．轨道垂向耦合动力学理论，建立了列车一轨道一路隧过渡段垂向耦合动力分析模型．以钢轨挠度变化率、车体加速度和轮轨力等作为评价指标，对路隧过渡段动力特性进行分析，提出了路基与隧道内同时设置过渡段时，减振橡胶垫层的刚度建议值和布置方式，以及仅在隧道内设置过渡段时过渡段长度的建议值．研究结果表明：过渡段橡胶垫层的刚度可采用分级过渡的方式，减振橡胶垫层的刚度比不宜超过2；在过渡段，以车体振动加速度为控制指标，从保障行车安全和减小过渡段维修工作量的角度出发，建议隧道内过渡段的设计长度为25～30m．

In order to choose a proper length of the transition section and minimize the change of rail deflection between the subgrade-tunnel transition section on the negative impacts of track safety and the ride comfort, a vertical coupling dynamic model of CRTS Ⅲ slab track in subgrade-tunnel transition section was established using the finite element method and vehicle-track coupling dynamics theory. In this model, the change rate of rail deflection, vehicle acceleration, and wheel-rail force are taken as evaluation indexes to characterize the dynamic behavior of the system in the transition section. Through analysis, reasonable stiffness and layout of anti-vibration rubber pad is suggested for the transition section with the damping cushion set up both in subgrade and tunnel, and the length of transition section is proposed for the transition section with the damping cushion set up in tunnel only. The results indicate that a hierarchical stiffness of the anti-vibration rubber pad can be applied in the subgrade-tunnel transition section, and the stiffness ratio should be no more than 2. In order to ensure the running safety and reduce the workload of maintenance and repair in the subgrade-tunnel transition section, the length should be within the range of 25 - 30 m for controlling of the vertical acceleration of car body.