地铁振动对邻近建筑物影响及围护桩减振效果研究

依托北京某拟建住宅项目,采用现场监测方法获得地铁列车运行引起建筑物场区内地面振动的振动特性,并通过有限元分析软件建立地铁-土体-建筑一体化三维数值模型,预测拟建楼房的振动规律,预测结果与现场监测结果对比显示二者有良好的一致性,并分析采取基坑围护桩作为减振措施的应用效果。研究结果表明:(1)在地铁运行影响下,地面振动加速度级随着频率增加呈现先增大后减小的趋势;(2)对于10层左右的建筑物,地铁运行振动引起的动力响应随着楼层的增加,存在一个先减小后增大的过程,地面首层和顶层的动力响应最为显著;(3)基坑围护桩能有效减小建筑振动响应,各典型楼层最大Z计权振动加速度级均下降7~9 dB;(4)随着楼层的升高,建筑结构对30~40 Hz频段的建筑物竖向振动具有一定削弱作用。

Study on the Effects of Subway Vibration on Surrounding Buildings and Damping Effect of Foundation Pit Support Pile

Based on a proposed project in Beijing,vibration characteristics of the ground in the building site area caused by the vibration of the subway train were obtained by on-site monitoring.Vibration law of the proposed buildings was predicted by establishing the three-dimensional numerical model of subway-soilbuilding.Comparison of the predicted results with the on-site monitoring results shows good agreement.Vibration damping effect of the foundation pit support pile was analyzed.The results show that:(1)under the influence of subway operation,the ground vibration acceleration level tends to increase and then decrease with increasing frequency.(2)For a building of about ten stories,the dynamic response caused by the vibration of subway operation tends to decrease and then increase as the number of floors increases,and the dynamic response of the ground floor and the top floor is most significant.(3)The foundation pit support pile can effectively reduce the vibration response of the building,and the maximum Z-weighted vibration acceleration level of each typical floor is reduced by 7~9 dB.(4)With the rise of the floor,the building structure plays a certain weakening role in the 30~40 Hz frequency band of the building vertical vibration.