十字交叉型地铁车站结构的振动台试验研究

Shaking table tests for cross subway station structure

随着近些年地下轨道交通的发展,十字交叉型地铁车站广泛的应用在实际工程中,了解并提高此类地铁车站的抗震性能具有重要意义。首次利用振动台试验的方法探究此类地铁车站结构,揭示了地震动在场地中的传播特性以及十字交叉型车站结构的地震响应特性,尤其是车站交叉换乘连接段对车站整体结构的抗震性能的影响。结果表明:地震波的传播受到场地特性影响明显,尤其是与场地卓越频率相近的部分,响应频谱被明显放大;随着地震动增强,场地的放大效应会有所减弱,但是场地的加速度响应放大谱的分布更加丰富,在拓宽场地响应频谱范围的同时也提高了地铁车站的地震风险。与此同时,在不同工况条件下车站结构模型的交叉换乘段对车站整体结构的影响基本在1.5倍的结构宽度以内,当距离超过该范围后,结构模型不再受其影响。与单体车站相比,此类车站交叉换乘连接段的底层结构更不利于抗震。上述结论可为了解并提高此类地铁车站的地震响应特性以及后续的抗震设计提供了有力支持。

With development of underground rail transit in recent years,cross subway stations are widely applied in practical engineering.It is of great significance to understand and improve aseismic performance of such subway stations.Here,for the first time,the shaking table test method was used to study such a subway station structure to reveal propagation characteristics of ground motion in the station area,seismic response characteristics of the station structure,especially,the effects of the station’s cross transfer linkage segment on aseismic performance of the station’s overall structure.Test results showed that propagation of seismic wave is obviously affected by the site’s characteristics,especially,seismic wave’s part with frequencies close to the predominant frequency of the site,the site response spectrum is obviously amplified;with ground motion enhancing,the amplification effect of the site can be weakened,but the distribution of the acceleration response amplification spectrum of the site is more abundant,the spectrum range of the site response is widened and the seismic risk of the station rises;at the same time,under different working conditions,the influence of the interchange segment of the station structure model on the station overall structure is basically within 1.5 times of the structure width;when the distance exceeds this range,the structure model is no longer affected by the interchange segment of the station;compared to the station with a single body,the bottom structure of the cross type station is more unfavorable to earthquake resistance;the above conclusions can provide a strong support for understanding and improving seismic response characteristics of such subway stations and the subsequent aseismic designs.