无砟轨道-箱梁结构振动传递及参数影响分析

摘要

With the wide use of the track-bridges in railroad transportation engineering, the vibration and noise problem of the bridge structure caused by high speed trains is being paid close attention to. In this paper, with a 32 m ballastless-track box-girder bridge as an object, the numerical model of the coupled system of the track, slab, CA mortar, concrete base and the box girder is set up for the analysis of the vibration transmissibility and parameters influence of the bridge vibration. The result shows that the attenuation of the low frequency vibration below 10 Hz is slower than the higher frequency vibration;the lateral vibration level below 10 Hz of the web of the box girder is about 10%of that of the vertical vibration, however, both lateral vibration and vertical vibration are nearly in the same level for the frequencies above 10 Hz;appropriate bridge supports have some vibration reduction effect for the low-frequency vibration, while the flexible fasteners have a vibration reduction effect for the box-girder bridge in the high-frequency range of vibration, and the CA mortar layer stiffness has less impact on the vibration of the bridge structure;the fasteners with low stiffness can reduce the vibration of the bridge but can intensify the track vibration. The results are helpful for the vibration and noise reduction design of the track bridges.%随着高架桥梁在轨道交通中的广泛应用，轨道交通引起的桥梁结构振动与噪声问题越来越引起人们的关注。以常见的无砟轨道-箱梁结构为研究对象，考虑常用的扣件、桥梁支座及CA砂浆性能参数，基于轨道和桥梁振动理论建立钢轨-轨道板-CA砂浆层-基座-桥梁系统空间实体振动分析模型，以轨道和桥梁结构的位移导纳为考核指标，分析振动在无砟轨道-箱梁结构中的传递，研究各关键参数对振动衰减的影响。计算结果表明：高速列车运行引起的10 Hz以内的低频振动衰减较慢，10 Hz以上的振动随着频率的增加衰减速度逐渐加快；桥梁腹板10 Hz以内的横向振动幅值约为竖向振动的10%，10 Hz以上两者振动水平相当；桥梁支座对桥梁结构低频振动有一定减振作用，而弹性扣件对中高频的桥梁结构振动有减振作用，CA砂浆层刚度对桥梁结构的振动影响较小；低刚度扣件减小桥梁振动的同时，会加剧较高频率的钢轨振动。计算及分析结果可为高速铁路桥梁结构的减振降噪设计提供参考。