桥墩沉降下纵连板式轨道与桥面间动态#br# 接触行为及其对列车动态特性的影响

桥墩沉降在高速铁路运营过程中不可避免，其会导致纵连板式轨道与桥面之间的变形不协调，进而引起底座与桥面之间的动态接触行为，恶化轨道力学性能并最终影响列车正常运行。这对这一问题，文章首先研究该动态接触过程的产生机制，并基于列车-轨道-桥梁动力相互作用理论提出纵连板式轨道和桥面间动态接触行为的研究方法；借助该方法从静态与动态两个角度研究桥墩沉降下轨道-桥梁动态接触行为；在此基础上探讨列车通过时的动态特性。结果表明：桥墩沉降和列车荷载会导致底座与桥面出现三处明显的动态接触区域；桥墩沉降导致的相邻桥墩处梁体上拱位移远小于沉降桥墩处的梁体下沉，但是沉降对上拱区域力学特性的影响却不可忽略；轨道的纵向连接特性可以在一定程度上缓解高速列车通过沉降区域时的振动；轨道随机不平顺不能完全掩盖桥墩沉降对系统动态特性的影响，表明沉降对系统的影响是不可忽视的。

Dynamic contact behavior between longitudinally-connected-track and #br# bridge deck subject to pier settlement and its influence on running train

Pier settlement is unavoidable for high-speed railways, directly causing the nonlinear contact behavior between longitudinally-connected-track and bridge deck and further affecting the dynamic performance of running train. Aiming at this problem, this work firstly studies the mechanism of contact between track and track. Then, based on the train-track-bridge dynamic interaction theory, a methodology is proposed, and the nonlinear contact behavior between track and bridge is investigated. Finally, the track stiffness caused by contact behavior and its influence on running train are determined. Results show that, there are three gaps between track and bridge. The upward movement of adjacent pier caused by the settlement pier is much smaller than the settlement at the settlement pier location, while the influence of pier settlement on upheaval region can’t be ignored. The longitudinal connection characteristics of track can alleviate the train vibrations to some extent.