强震下地铁车站结构动力响应特性

Dynamic response characteristics of underground subway station during the strong earthquake

研究地下结构在地震中的动力响应,对地铁的建设和安全运营有重要的现实意义。根据试验条件和Bock ingham定理,作者确定了试验相似比,针对北京地区的地质条件和典型的地铁车站结构进行了大型振动台试验,并对得到的加速度时程进行了分析。通过分析,发现土与地下结构间存在相互作用,但地下结构不会表现出其自振频率,而是随着土体一起振动;在低强度地震下,地下结构对土体影响较小;在高强度地震下,地下结构对土体影响较大;峰值加速度的放大倍数不会超过2,且同一点的放大倍数基本保持不变;随埋深的增加,卓越频率和其振幅会减小,且加速度峰值也有相似的规律。

It is important to study the seismic behavior on a subway station for its construction and safe management.According to the test conditions and Buckingham Theorem,the dynamic similarity coefficients are given,and the shaking table test of model is made to simulate a typical subway station structure in soil with specific concerns to the geological conditions in Beijing area.Based on the analysis of the acceleration history curves on the model,it is concluded that the interaction between the structure and the soil exits,but the underground structure doesn＇t behave in its natural frequencies,and vibrates togather with the soil.Under the low intensity earthquake,the underground structure will exert a very small influence on the soil;under the high intensity earthquake,the underground will exert a large influence on the soil.Moreover,the following conclusions are drawn that the magnification of the peak acceleration is no more than 2 times for the model.With the depth increase,the dominant frequency and its amplitude decrease,and the peak acceleration also does.With the intensity increase,the peak acceleration magnification is basically invariable at the same point.