考虑加载历史多因素耦合作用下的梁轨相互作用附加力

Additional force of track-bridge interaction under multi-factor coupling of loading history

目前,大多数考虑加载历史的梁轨相互作用研究都集中在梁桥、拱桥以及斜拉桥等桥型上,对于悬索桥上考虑加载历史的梁轨相互作用研究还存在不足,采用理想弹塑性滞回模型模拟道床纵向阻力,建立以五峰山大桥为研究对象的高速铁路大跨度悬索桥梁轨相互作用分析模型,研究多因素耦合作用时加载历史对梁轨相互作用附加力的影响规律,以及往复荷载和循环荷载作用后道床纵向阻力的滞回特性对于梁轨相互作用产生的残余应力及位移的影响规律。分别采用加载历史法和线性叠加法计算温度、挠曲和制动荷载耦合作用下钢轨纵向附加应力,分析往复荷载和循环荷载作用下钢轨内部残余应力和梁轨残余相对位移的分布特点。研究结果表明:在多因素耦合作用下,虽然2种方法的梁轨相互作用附加力分布规律总体趋势保持一致,但是线性叠加法计算结果相较于加载历史法过于保守;钢轨在往复荷载和循环荷载作用下存在明显残余应力且经历过一次循环后其内部的残余应力就能达到收敛的稳定值,这是道床纵向阻力的弹塑性滞回特性决定的;温度因素不管是在多因素耦合作用下还是在往复或者循环荷载作用下对梁轨相互作用附加力的产生都占据主导地位,表明温度作用对考虑加载历史的悬索桥上梁轨相互作用有重要影响。

At present most of the research on track-bridge interaction considering loading history is focused on beam bridges, arch bridges and cable-stayed bridges. There are still deficiencies in the research on track-bridge interaction considering loading history on suspension bridges. In this paper, the ideal elastic-plastic hysteretic model was used to simulate the longitudinal resistance of track bed.The track-bridge interaction analysis model of high-speed railway long-span suspension bridge with Wufengshan bridge as the research object was established.The influence of loading history on the additional force of track-bridge interaction under multi-factor coupling and the influence of hysteretic characteristics of longitudinal resistance on the residual stress and displacement of track-bridge interaction under reciprocating and cyclic loading were studied. The longitudinal additional stress of rail under the coupling action of temperature, deflection and braking load was calculated by loading history method and linear superposition method respectively. The distribution characteristics of residual stress in rail and residual relative displacement of beam and rail under reciprocating load and cyclic load are analyzed. The results show that under the action of multi-factor coupling, although the general trend of the additional force distribution of track-bridge interaction between the two methods is consistent.The calculation results of linear superposition method are too conservative compared with the loading history method. There is obvious residual stress in rail under the action of reciprocating load and cyclic load, and the residual stress in rail can reach the stable value of convergence after a cycle, which is determined by the elastic-plastic hysteretic characteristics of the longitudinal resistance of rail bed. The temperature factor plays a dominant role in the generation of additional forces of trackbridge interaction, whether under the action of multi-factor coupling or reciprocating or cyclic loading.This result indicates that temperature has an important influence on the track-bridge interaction of suspension bridges considering loading history.