高架轨道结构振动特性分析

目前高架轨道是城市轨道交通的主要结构型式之一,为分析其结构振动特性,通过建立高架轨道垂向振动解析梁模型和有限元模型,采用动柔度法计算高架桥速度导纳和轨道速度导纳,并分别考虑桥梁支座刚度、桥梁截面形状对高架桥振动的影响以及高架桥基础和扣件刚度对轨道结构振动的影响。结果表明,桥梁支座刚度和截面形状在低频段对高架桥的振动有较大的影响,在高频段影响较小;高架桥结构对轨道的振动在20 Hz以下有明显的影响,在20 Hz以上基本没有影响;提高扣件刚度有利于减小轨道的竖向振动,但同时增大了轨道的固有频率。

Analysis on Vibration Characteristics of Elevated Track Structure

At present,the elevated rail is one of the main structure forms in urban rail transit. In order to analyze the structure’s vibration characteristics,this paper,through establishing the viaduct vertical vibration model of analytical beam and finite element model and by using the dynamic compliance method to calculate the viaduct velocity admittance and orbital velocity admittance,studies the influence of bearing stiffness and the bridge cross section shape on the viaduct bridge vibration. Meanwhile,it probes into the influence of the viaduct foun-dation and fastener stiffness on track structure vibration. Results show that,at low frequency,the bearing stiff-ness and cross section shape have a larger effect on the viaduct vibration,while at high frequency,it has little in-fluence;Under 20 Hz,viaduct structure on the vibration of the rail has obvious effects,and it has no effect when above 20 Hz . This paper concludes increasing the stiffness of fastener is beneficial for reducing the vertical vi-bration of the rail,but may increase the natural frequency of the orbit at the same time.