上盖单塔框架结构时大底盘地铁车站的地震响应

Seismic Response of Large Chassis Subway Station under Upper Cover Single Tower Frame Structure

以某上盖6层框架结构的大底盘地铁车站工程为研究背景,基于有限元软件Midas GTS-NX,建立土体-大底盘地铁车站及其上盖单塔框架结构体系的三维数值模型,分析上盖框架结构对大底盘地铁车站结构地震动力响应的影响。结果表明:在输入地震动作用下,上盖框架结构的存在增大了地铁车站结构的内力,且上盖结构层数越多,内力增幅越大;车站柱子与上盖框架结构相距越近,其弯矩幅值越大、剪力幅值越小;车站柱子横截面弯矩幅值沿柱高方向呈近似"W"形分布,车站顶板和底板弯矩幅值沿车站横向均呈锯齿状分布,但底板弯矩极值分布较均匀,车站侧墙最大弯矩发生在底部区域;车站发生的变形仍为剪切型,上盖结构的存在只改变其相对位移峰值大小,而未改变其变形模式;车站柱子的振动峰值加速度自下而上逐渐增大;对大底盘地铁车站及其上盖结构体系中的地下结构进行抗震设计时,无须考虑上盖结构对地下结构惯性力改变的影响。

Taking the actual engineering of a large chassis metro station with upper 6-story frame structure as the research background,a three-dimensional numerical model of soil,large chassis subway station and its upper cover single tower frame structure was established based on the finite element software Midas GTS-NX.The influence of the upper cover frame structure on the seismic dynamic response of subway station structure was analyzed.Results show that,under the action of input ground motion,the existence of the upper cover frame structure increases the internal force of the subway station structure,and the more the stories of the upper cover structure,the greater the increase of the internal force.The closer the distance between the station column and the frame structure is,the greater the bending moment amplitude is and the smaller the shear amplitude is.The bending moment of the cross section of station column is approximately distributed W-shaped along the column height.The bending moments of station roof and floor are zigzag along the transverse direction of the station.However,the extreme bending moment of the floor is distributed more uniformly.The maximum bending moment of the station side wall occurs in the bottom area.The deformation of the station is still shear type,and the existence of the upper cover structure only changes the peak value of the relative displacement,but does not change its deformation pattern.In addition,the peak acceleration of the station column increases gradually from bottom to top.It is not necessary to consider the influence of the upper cover structure on the inertial force change of the underground structure in the seismic design of the underground structure in the system of large chassis subway station and its upper cover frame structure.