高速铁路大高差桥墩竖向温度变形对行车舒适性和安全性影响研究

墩顶竖向变形是高速铁路桥梁安全的重要参数之一。在温度效应下,相邻桥墩高差较大时,桥梁会出现竖向变位差,造成轨道不平顺,这将影响高速铁路的舒适性和安全性。目前国内各类规范对桥墩竖向变形的限值规定不尽相同,为了研究大高差桥墩顶竖向变形的温度效应影响,以合福高铁巷坑大桥为例,对大高差桥墩在温度效应下的墩顶竖向变形进行现场测量,将测量和计算结果同各类规范进行对比,进一步对考虑温度效应时车辆通过桥梁结构时耦合响应进行仿真分析,结果表明:巷坑大桥桥墩顶竖向变形差超过规范限值,但车辆通行时的舒适性和安全性均能满足规范要求,车辆走行性偏于安全,合福高铁通车至今该桥一直运营正常。综上所述,现行规范对大跨度桥梁桥墩的变形指标要求偏严,特殊情况下无法满足规范要求时,建议参考公式,适当放松验收指标。本研究对突破规范限制,在大跨度桥梁铺设无砟轨道具有重要的意义。

Influence of Vertical Temperature Deformation of High-speed Railway Bridge Pier of Large Height Difference on Riding Comfort and Safety

The vertical deformation of bridge pier top is one of the important parameters of bridge safety. Under the temperature effect, when the height differences of adjacent bridge piers are large, the vertical deflection difference of the bridge will occur, resulting in uneven track and affecting the comfort and safety of the high-speed railway. At present, the limits of vertical deformation of bridge piers are different in domestic codes. In order to study the effect of temperature on vertical deformation of bridge piers, the Xiangkeng bridge on the Hefei-Fuzhou high-speed railway is taken as an study case. The vertical deformation of the pier top under the temperature effect of the large height difference pier is measured on site, and the measurements and calculation results are compared with various codes. Further, simulated analysis of the coupling response of the vehicle passing through bridge structure with temperature effect is conducted. The results show that the vertical deformation difference of the Xiangkeng bridge exceeds the standard limit, but the comfort and safety of the vehicle meet the requirements of the specification, and the vehicle mobility is safe. To sum up, the current code is somewhat stricter in requirements for the deformation of long-span bridge piers. When it can not meet the specification requirements under special circumstances, it is recommended to refer to the formula and relax the acceptance index appropriately. This study is of great significance for breaking through the limitation of codes and laying ballastless track on long-span bridges.