高速铁路高架桥周围场地振动反应谱分析EI北大核心CSCD

基于达朗贝尔原理、无限周期结构理论以及具有完全匹配层的薄层法-容积法建立了高速列车-周期性桥梁结构-群桩基础-地基土动力相互作用耦合模型,提出了一种半解析-半数值方法以预测和评价高架轨道交通引起的周围场地振动,并对该方法进行了程序实现及有效性验证。进一步提出了场地振动反应谱的概念,并通过算例分析了不同行车速度、场地卓越周期以及地表不同接收点的场地振动反应谱特性,进而得到高速铁路周围环境振动基于规范容许值的阈值范围。研究结果表明,场地地面不同接收点的垂向位移最大值和振级响应均随场地卓越周期的增大而呈增大的趋势,但振级响应在局部位置处出现了放大现象;以地面位移最大值为指标的场地振动反应谱能反映振动的变化速率,而以总体振级VLz为指标的场地振动反应谱则能反映场地卓越周期、与桥墩中心线距离以及行车速度对场地振动响应的局部特性,因此在场地反应谱中对评价指标的选取应综合考虑。本文所提出的场地反应谱和振动阈值图不仅可以为拟建构筑物提供满足不同振动限值所需的距离参考,而且可以为既有构筑物受到的高架轨道交通环境振动影响进行评价。

Response spectrum analysis of field vibrations surrounding high-speed railway bridge

In order to predict and evaluate the environmental vibration caused by the viaduct rail traffic,this paper proposes a semi-analytical and semi-numerical method,in which the high-speed train-periodic bridge-pile group foundation-soil coupling model is established on the basis of the d’Alembert principle,the infinite periodic structure theory and the thin layer method with perfectly matched layer-volume method.Furthermore,the prediction method is accomplished by Matlab programming and validated by existed results.The concept of field vibration response spectrum(FVRS)is proposed,whose characteristics are analyzed by a numerical example,respectively from the influence of train speed,predominant period of site soil,and the location of the ground measurement points.At the same time,the environmental vibration threshold induced by the high-speed train running on the bridge is obtained in conjunction with the relevant specification allowances.The research results show that the vertical displacement maximum and vibration level of ground vibration have the tendency of increasing with the predominant period of site soil,while there exists the amplifying phenomena in vibration level for certain ground receivers.When the maximum vertical displacement is taken as the evaluation index of ground vibration,the FVRS can reflect the variety velocity of ground vibration.When the vibration level VLz is taken as the evaluation index,the FVRS can reflect the local properties and effects of site predominant period,distance away from the center of bridge pier and train speed.So the choose of vibration evaluation index should be comprehensive.The FVRS and the vibration threshold graph cannot only provide the referenced rational location surrounding the rail traffic for the proposed building under the requirement of meeting different vibration allowances,but also evaluate the influence of environmental vibrations induced by viaduct rail traffic on existed buildings.