高架路交通诱发的地面振动测试与分析

Test and Analysis of Ground Vibration Induced by Elevated Road Traffic

为了研究高架路交通诱发地面振动在土层中的振动特性与传播规律,对多个路段高架路诱发的地面振动进行实测,大量统计分析结果表明:由高架路交通诱发的地面振动以竖向振动为主,优势频率为5～25Hz;随着振源距的增加,竖向振动呈非完全指数衰减,在一定距离处略有放大,水平振动大小随振源距的增加呈正弦曲线形状分布;并指出地面振动大小与高架路上行驶的车辆荷载、车速、桥面平整度指数、桥面伸缩缝、桥墩基础形式、场地土动力特性、波断面以及减隔振措施有关,提出采用组合函数法预测Z振级能够较好地反映出振动放大区以及其他多因素对地面振动的影响,并给出预测公式。

To study the vibration induced by elevated-road traffic and its propagation rules in soil,field measurements were carried out in different sites. Large numbers of statistics indicate that:the ground vibration induced by elevated road traffic is vertical vibration primarily,whose dominant frequency ranges from 5 to 25 Hz. The vertical vibration do not always attenuate exponentially with the increasing distance from the vibration source to the measurement location,for there is a vibration amplified region at a certain distance and the horizontal vibration intensity follows a sine-distribution. The ground vibration is related to multi-factors as the vehicle load,the vehicle velocity,the international roughness index(IRI) of the road,the expansion joint,the basement form,the soil dynamic performance,the wave cross-section and the vibration reduction methods. The combination-function method which could reflect the effect of the vibration amplified region and other multi-factors was proposed to forecast the Z-direction vibration levels. The relevant forecast fomula for Z vibration levels was given,which had a better fitting effect than the conventional methods.