地铁振动的传递及对建筑物的影响实测与分析

In situ Measurement and Analysis of Subway Vibration’s Transmission and the Influence to Nearby Buildings

摘要:

在上海市某软土场地对地铁隧道诱发的三向环境振动进行了监测，结合连续小波变换及1/3倍频程分频振级，对隧道内与自由场地的振动频谱特性及传递规律等进行了分析，同时对邻近建筑的室内舒适度作了评估.测试结论包括如下方面：①轨道扣件上的三向振动表现出明显的宽频和冲击振动特性，经隧道衬砌的第1层滤波效应后，传递至其中部的竖向和横向振动均相对平稳，且衰减效应明显.②传递至自由场地的三向振动，经土层的反射和折射效应后，呈现出与列车编组对应的冲击振动特性；其与衬砌上的频率成分基本相似，但振幅衰减效应不如衬砌，甚至会出现一定幅度放大.③经建筑墙体的第3层滤波效应后，竖向振动传递至楼板后其频率成分单一，对室内舒适度影响很大，其分频振级的峰值位于楼板的竖向自振频率处，是影响室内舒适度的决定性因素.④地铁引起的地面高频振动激发了建筑结构的水平向高阶振型，对部分楼层的舒适度具有潜在影响，应引起注意.上述测试结论有助于为地铁环境振动有针对性地设计相应减振及隔振措施提供参考.

Abstract:

The three dimensional environmental vibrations induced by a shallow buried subway in Shanghai were in situ measured. By applying with continuous wavelet transform and 1/3 octave frequency vibration level, the vibration transferring characteristics between the tunnel and the open field were analyzed. Simultaneously to the human comfort inside a nearby six story residential building. Testing results include 4 aspects: ① the 3 D vibrations on rail pads were characterized by wide banded and shocking. The vertical and transverse vibrations were relatively smooth after transferred to the center of lining, but amplitudes attenuated greatly. ② The 3 D vibrations in the open field transferred from lining were obviously shocking vibration characteristics corresponding to the carriages. The frequencies were the same with the lining, but the amplitudes attenuated smaller, sometimes maybe magnified. ③ After transferred through the third filter system represented by the masonry walls of building, the vertical resonance frequencies of floor slabs were corresponding to the peak values of the vertical octave vibration levels in this testing, and were the main factor influencing the human comfort inside building. ④ The horizontal high frequencies transferred from subway tunnel have potential influences on some floors’ human comfort, need to be paid more attentions. The above measurements will be benefited to the design of vibration reduction methods to railway vibrations specifically.