地铁车站深基坑开挖稳定性与抗震分析

Stability and Seismic Analysis on Deep Foundation Pit Excavation in Subway Station

以合肥市轨道交通4号线金寨路站深基坑为背景,利用FLAC 3D软件建立了地铁车站深基坑的数值计算模型,分析了基坑开挖过程中基坑周边土体和桩体的竖向位移、水平位移和支撑轴力,并进一步研究了地震荷载作用下基坑主体结构的竖向位移、水平位移和内力。研究结果表明:基坑开挖过程中,最大地表沉降、桩体水平位移和支撑轴力分别为33.6 m、27.8 m和1528.5 kN;主体结构顶板以及侧墙的竖向位移和水位位移的最大差异值分别出现在地震后4 s和8.5 s,分别为18 mm和10 mm;地震荷载作用下车站立柱比侧墙更容易发生压裂破坏。

As a research background of deep foundation pit of subway line 4 Jinzhai road station in Hefei city,the numerical calculation model of subway station deep foundation pit was established by FLAC 3 D numerical software,the horizontal displacement,vertical displacement and strut axial forces of pile body,foundation pit and surrounding soil were analyzed under the process of foundation pit excavation.And the vertical displacement,level displacement and internal force of the main structure were studied under seismic load.The research results show that:the maximum surface settlement,horizontal displacement of pile and axial force of support are 33.6 m,27.8 m and 1528.5 kN respectively in the process of foundation pit excavation.The maximum difference values of vertical displacement and water level displacement of the roof and side walls of the main structure appeared 4 s and 8.5 s after the earthquake,which were 18 mm and 10 mm respectively.Under the action of seismic load,the station columns are more prone to fracture than the side walls.