高铁气动荷载作用下隧道衬砌开裂体动力响应分析

Dynamic response analysis of cracked block in tunnel lining under aerodynamic load of high-speed rail

根据高速铁路隧道衬砌壁面气动荷载特性,在理论分析及模型试验基础上,采用数值模拟对列车风作用下衬砌开裂体固有频率和动力响应进行研究,分析了衬砌开裂体尺寸和气动荷载加载频率及峰值的影响,对气动荷载作用下衬砌裂损处的安全性进行辨识.结果表明:开裂体固有频率与自身厚度之间存在线性关系,并随其长度增加而快速降低,下降幅度最高可达70.29%;开裂体位移响应随外荷载峰值增加而增加,且与荷载加载周期数正相关.外荷载频率接近结构固有频率时,结构的位移和速度均显著增加.当荷载频率为1和5 Hz时,开裂体悬臂端位移峰值分别为荷载频率3 Hz时的10.75%和13.62%.

According to the aerodynamic characteristics of high-speed railway tunnel lining wall,the intrinsic frequency and dynamic responses of lining cracks under the action of train wind were studied by numerical simulation based on theoretical analysis and model tests.The effects of the lining crack dimensions and the loading frequencies and peak values of the aerodynamic loads were analyzed.The safety of the lining cracks under the action of the aerodynamic loads was identified.The results show that the intrinsic frequency of the cracked body has a linear relationship with its thickness.It decreases rapidly with the increase of the thickness,and the decline rate is up to 70.29%.The displacement response of the cracked body increases with the increase of the peak value of the external load,and is positively correlated with the number of the loading cycles.When the frequency of the external load tends to approach to the intrinsic frequency of the structure,the displacements and velocities increase obviously.When the loading frequencies were 1 and 5 Hz,the peak displacements at the cantilever end of the cracked body were 10.75%and 13.62%of that with the loading frequency of 3 Hz,correspondingly.