高架地铁列车环境振动传播规律的数值模拟

Numerical simulation of environmental vibration induced by viaduct rail transit

为研究地铁诱发的环境振动在周围土体和邻近建筑物内的传播规律,建立了31自由度地铁车辆模型以及桥梁-土体-建筑三维有限元模型,并进行了数值研究.首先,通过三角级数法获得可靠的轨道不平顺谱,建立车辆-轨道动力学模型,得到车辆随机振动荷载时程谱;然后,将荷载时程谱加载到桥梁-土体-建筑三维有限元模型上,计算得到周围土体和临近建筑内关键点位的振动幅值,并对计算结果进行频谱分析,获得各点的振动功率谱函数.研究结果表明:地铁环境振动在地面上的传播存在明显的方向性,竖向振动占主导地位;高层建筑12层以上部分需重点考虑水平面上的振动;传播过程中10 Hz以上的高频振动衰减较快,距轨道中心30 m以外的环境振动以低频振动为主.

To study the environment vibration and its effect on surrounding soil and structures around,a 31-degree freedom vibration model of metro vehicle and a three-dimensional finite element model of bridges-soil-building w ere proposed.First,the track irregularities w ere simulated by the trigonometric series method.A vertical vehicle-track coupling model w as developed and the time-history loads of metro vehicle w as obtained.Then,a three-dimensional finite element model of bridges-soil-building w as set up and the time-history loads w ere utilized to analyze the effect of accelerate parameters on the key points in ground and buildings.The calculation results w ere analyzed by the spectral analysis method,and the pow er spectrum functions of the key points w ere obtained.The results of this study show that the environment vibration on the ground has significant directionality characteristic,and vertical vibration plays a dominant role.The horizontal vibration becomes a major concern in the high-rise building above 12-storey.The high frequency vibration component above 10 Hz attenuates faster than the component below 10 Hz.The vibration in the area 30 m aw ay from the line is mainly of the low frequency.