【摘要】 利用在北京地铁4号线北京大学东门站附近地铁隧道内和地面场地观测得到的振动数据,提出一种基于独立信号的谱时程比方法,实现了从地铁振动和地面振动数据中提取地层场地响应信息以及土层中的振动衰减信息.该方法对同一观测点不同时间段观测数据的分析结果具有高度的稳定性,经验证与基于钻孔资料地层模型的半无限空间层状介质的理论传递函数的频率响应特征具有良好一致性.同时,基于该方法还对隧道壁与土层振动耦合以及观测点附近浅表土层非弹性吸收带来的综合等效衰减特征进行了评估.研究结果显示,北京大学东门站附近振动场地放大效应的峰值频率主要在3—10 Hz之间,受地铁振动的影响.场地效应在不同测点以及地铁沿线、切线和铅垂线等3个不同方向显示出一定的差异.更多还原

【Abstract】 We deployed seismometers in subway tunnels and on ground in the vicinity of East Gate of Peking University Station of Beijing Subway Line 4.Using the vibration data obtained,we proposed a data processing method based on independent signals,which we called spectrum-time history ratio method,thus we could obtain stratigraphic site effect and the information of vibration attenuation characteristics from subway vibration data and ground vibration data.Vibration data from different time periods in the same observation point are analyzed and calculated.The results are highly stabilized and proved a good consistency with frequency response characteristics of theoretical transfer function applied in layered half-space medium model based on borehole data.Meanwhile,we also evaluated integrated equivalent attenuation characteristics induced by coupled vibration of tunnel wall and the soil and inelastic absorption of upper layers near the observation points based on the method.Our results indicate that the peak frequencies of site amplification effect of vibration range mainly between 3—10 Hz near the East Gate of Peking University Station.Affected by the vibration of the subway,site resonance exhibits a strong dependence on direction and a spatial variation.更多还原