地铁及地面交通环境振动实测与数值模拟研究

选取某城市具有代表性Ⅱ类场地地铁与道路交通重合段，对环境背景、地铁单独通过、重载车辆单独通过、地铁和重载车辆同时通过开展振动实测，利用Z振级和1/3倍频程频谱进行数据分析，同时建立简化有限元数值模型，并将模拟结果与实测结果进行对比分析以评价沿线环境振动影响.结果表明，简化理论分析模型可基本满足工程应用要求；地铁与重载车辆引发的环境振动衰减规律总趋势是随着水平距离的增加而呈现先迅速后平缓的减小过程，有地铁作用时，30m附近存在振动放大区；地铁与重载车辆单独作用时存在稳定的环境振动主频分别为50~60Hz和16Hz，两者共同作用存在变化范围为16~80Hz的不稳定特定主频，其变化规律符合交通类型的主导地位；当水平距离超过60m后，环境振动体现场地卓越周期，可忽略地铁及重载车辆振动影响；对于加速度频率在1Hz内的低频振动，距离和交通荷载类型的影响均不明显.研究成果可为地铁及地面交通选线设计和沿线环境振动及控制提供工程参考和理论预测依据.

Field measurement and numerical simulation on environmental and vibration effects induced by metro and ground traffic loads

To measure the ground vibration under four conditions, the environmental vibration, metro passing alone, heavy-duty vehicles passing alone, metro and heavy-duty vehicles passing jointly, a representative Class II field with the overlapping section of metro and ground traffic was selected in a certain city, and the degree of Z-direction vibration and the 1/3 octave spectrum were used to analyze the field vibration data. A simplified numerical model was established and compared with the measured results to evaluate impacts of environmental vibration along the road line. The results show that the simplified model generally met the engineering requirements. The environmental vibration caused by metro and heavy-duty vehicles decreased rapidly at first, and then gently with the increase of horizontal distance away from the road centerline. A vibration magnification zone was observed about 30meters away from the road centerline under metro passing. The ground vibration possessed the stable dominant frequency around 50~60Hz under conditions of metro passing alone, when heavy-duty vehicles passed alone, the dominant frequency became was 16Hz. While an unstable dominant frequency of about 16~80Hz was observed under the condition of metro and heavy-duty vehicles passing jointly, which was in line with the dominant position of traffic types. The influence of metro and heavy-duty vehicle passing could be ignored when the horizontal distance was more than 60meters. The same observation could be extended to the situation when the vibration frequency was lower than 1Hz. These research results could provide engineering reference and guidance to theoretical prediction for metro and ground traffic route selection, design, and vibration control.