用薄层法分析高架轨道交通引发的环境振动

Environmental vibration induced by elevated railway traffic using thin-layer method

薄层法是分析和模拟弹性波在层状介质中传播的一种半解析半数值方法。将由车辆-桥梁动力分析程序算得的高架轨道支架动反力作为支架的激振荷载。在支架上激振荷载作用下,利用薄层法计算位于上海典型场地上的高架轨道线路承台群桩基础周围地基的频率响应函数。根据频率响应函数和激振荷载可算得高架轨道线路周围场地的加速度响应及振级。分别采用单支架模型和多支架模型计算高架轨道交通引发的环境振动。振级计算结果与实测回归公式的比较表明,多支架模型中相邻基础的影响不大,实用时可采用单支架模型进行计算。本文提出的高架轨道交通环境振动分析模型可以应用于高架轨道交通引发环境振动的分析和预测。

The thin-layer method （TLM） is a semi-analytical and semi-numerical approach for the analysis of elastic wave propagation in stratified media.. The frame reactions, which were calculated by the computer program of the train-bridge system＇s dynamic analysis, served as the exciting loads on the elevated railway frame. The frequency response functions of soils surrounding the elevated railway frame supported on group piles foundation with footing, on the typical Shanghai soil site, were calculated by TLM. Based on the exciting loads and the frequency response functions, the acceleration response and vibration level of surrounding site can be obtained. Single frame model and multi-frame model were adopted to calculate the environmental vibration induced by the elevated railway traffic. The comparison between the calculated vibration level with that of the measured regressive formula shows that the model and method proposed in this paper is feasible for the evaluation of the environmental vibration induced by the Shanghai elevated railway traffic, and that the effect of the adjacent frames is very small. The analytical model proposed in the paper is feasible for the analysis and evaluation of the environmental vibration induced by elevated railway traffic.