地震-移动荷载耦合作用下地铁车站动力性能研究

Study on dynamic performance of metro station under seismic-moving load coupling

地下轨道交通是城市交通的生命线,由于我国地震频发以及列车进出站频率增加,地铁车站结构易受地震荷载和列车荷载共同影响,然而目前地铁车站结构抗震性能研究中未考虑地震-列车荷载耦合作用存在的现实问题。为保证地震和列车进出站同时发生时地铁车站结构的安全,建立土体-地铁车站-轨道相互作用的三维精细化计算模型,选取列车制动进站的荷载形式施加在轨道表面,并在模型底部输入三向地震波,对比分析地铁车站结构在地震作用和地震-列车耦合作用2种工况下的应力、位移和加速度的变化规律。研究结果表明:地震-列车耦合作用下,下层柱的柱底峰值应力最大,是车站结构最薄弱的位置,发生变形后首先达到最大屈服应力值并产生塑性破坏;在列车进站前期(0~5 s),板在地震-列车耦合作用下的加速度及位移幅值均大于地震作用下的加速度及位移幅值,列车进站后期,板在2种工况下的加速度及位移基本一致;在地震-列车耦合作用下,当地震加速度较小且列车速度较大时,两者振频接近产生共振,并导致对板的振动放大现象。

Underground rail transit is the lifeline of urban transportation.Due to the frequent occurrence of earthquakes and the increasing frequency of train entry and exit in China,the structure of subway stations is susceptible to both seismic and train loads.However,the current research on the seismic performance of subway station structures has not considered the practical problem of seismic and train load coupling.In order to ensure the safety of subway station structure when the seismic struck as the train was entering and leaving the station occur,a three-dimensional refined calculation model of soil,subway station and track interaction is established.The load form of train braking entering the station is selected to apply on the track surface,and the three-dimensional seismic wave is input at the bottom of the model.The variation law of stress,displacement and acceleration of subway station structure under the two working conditions of seismic action and seismic train coupling action is compared and analyzed.The results show that under the coupling effect of seismic and train,the peak stress at the bottom of the lower column is the highest,which is the weakest position of the station structure.After deformation occurs,the maximum yield stress value is first reached and plastic failure occurs.In the early stage of train arrival(0~5 s),the acceleration and displacement amplitudes of the board under seismic train coupling are greater than those under seismic action.In the later stage of train arrival,the acceleration and displacement of the board under both working conditions are basically the same.Under the coupling effect of seismic and train,when the seismic acceleration is small and the train speed is high,resonance occurs when the vibration frequencies of the two are close,leading to the amplification of the vibration of the plate.