双振源激励下地铁车辆段上盖建筑物振动特性

Vibration characteristics of metro depot upper building under double vibration source excitation

以广州某地铁车辆段为研究对象,实测了试车线与库内检修线引起地面振动的加速度,分析了两类振源的衰减规律与差异;建立了车辆段上盖建筑物有限元模型,将实测地面振动数据采用大质量法进行多点激励,分析了双振源激励对上盖建筑物楼板振动的影响。研究结果表明:列车通过时,试车线地面振动主要频率为60~80Hz,检修线主要频率为20~40Hz;试车线荷载振源强度大于检修线,约为6dB;试车线振动衰减率约为1.07dB·m^-1,检修线振动衰减率约为1.69dB·m^-1,说明检修线引起地面振动强度的衰减速度比试车线更快;与非一致激励相比,一致激励对上盖建筑物楼板10Hz以下振动影响显著,各层加速度级在2.5Hz处存在明显峰值,这与建筑物楼板的固有频率有关;试车线荷载激励下,底层楼板振动主要频率范围为40~60Hz,顶层出现在20~40Hz,峰值中心频率集中在40.0Hz处;检修线荷载激励下,各层楼板振动主要频率范围为0~40Hz,峰值中心频率集中在31.5Hz处;对比单一振源激励,双振源激励使建筑物楼板Z振级增加了0~3.5dB,这在地铁车辆段上盖建筑物的环境振动评价中应充分重视。

Taking a certain metro depot in Guangzhou as the research object,the accelerations of ground vibration caused by the testing line and the repairing line in the depot were measured,and the attenuation laws and differences between the two kinds of vibration sources were analyzed. The finite element model of metro depot upper building was established,and the measured ground vibration data were processed by multi-support excitation of large mass method.The influence of double vibration source excitation on the vibration of upper building floor was analyzed.Analysis result shows that when the train passes through,the main frequency range of ground vibration of testing line is 60-80Hz,and that of repairing line is 20-40Hz.The vibration source strength of testing line is greater than that of repairing line,which is about 6dB.The vibration attenuation rates of testing line and repairing line are about 1.07and 1.69dB·m^-1 respectively,which indicates that the attenuation speed of ground vibration strength caused by the repairing line is faster than the testing line.Compared with the non-uniform excitation,the uniform excitation has a significant effect on the vibration of below 10Hz for the upper building floor.The acceleration level of each layer has obvious peak at 2.5 Hz,which related to the inherent frequency of building floor.Under the load excitation of testing line,the main vibration frequency ranges of low and top floors are 40-60and 20-40 Hz,respectively,and the central frequency of peak is concentrated at 40.0Hz.Under the load excitation of repairing line,the main vibration frequency range of each floor is 0-40 Hz,and the central frequency of peak is concentrated at 31.5Hz.Compared with the single source excitation,the double vibration source excitation increases the degree of Z direction vibration level of building floor by 0-3.5dB,which should be paid full attention in the environmental vibration evaluation for the upper building of metro depot.2tabs,15figs,31refs.