地铁站深基坑桩撑支护开挖变形

Deformation of Pile Support Excavation in Deep Foundation Pit of Subway Station

以济南地铁邢村站基坑开挖支护为工程依托,通过理论分析、数值模拟和监控测量相结合的方法,首先在理论方面阐明基坑变形的理论依据,然后利用有限元软件ABAQUS对邢村站基坑开挖的全过程进行了模拟,并结合现场的监测结果,对基坑开挖过程中围护结构的水平与竖向位移和基坑周边的地表沉降以及支撑结构的轴力变化进行了分析。研究结果表明:随着基坑的开挖,基坑顶部呈现出逐渐向坑内运动的趋势,并且随着开挖过程中支撑结构的施加,围护结构整体呈现出向坑内变形的“弓”形分布,在支撑施加的部位,变形明显减小;由于基坑开挖土体的卸荷,围护结构出现隆起变形;地表沉降曲线呈现“U”形分布,并且随着基坑开挖深度的逐渐增加,地表沉降最大值逐渐增大,基坑开挖的影响范围基本在0~20 m内;各道支撑的轴力呈现出逐渐增加的趋势,下部的支撑发挥作用的效应更明显,并且下部支撑轴力大于上部支撑的轴力。

Based on the foundation pit excavation and support of Xingcun Station of Jinan Metro,through theoretical analysis,numerical simulation and monitoring measurement,the theoretical basis of foundation pit deformation was first expounded in theory,and then the whole process of foundation pit excavation of Xingcun Station was simulated by using the finite element software ABAQUS,and combined with the on-site monitoring results.The horizontal and vertical displacement of the retaining structure,the ground settlement around the foundation pit and the axial force change of the supporting structure during the excavation of the foundation pit were analyzed.The research results show that with the excavation of the foundation pit,the top of the foundation pit presents a trend of gradually moving into the pit,and with the application of the supporting structure during the excavation process,the retaining structure as a whole presents a“bow”shaped distribution of deformation to the pit.The deformation value decreases obviously.Due to the unloading of the excavated soil mass of the foundation pit,the retaining structure appears uplift deformation.The surface settlement curve presents a U-shaped distribution,and with the gradual increase of the excavation depth of the foundation pit,the maximum surface settlement gradually increases,and the influence range of the foundation pit excavation is basically within 0~20 m.The axial force of each support shows a gradually increasing trend,and the effect of the lower support is more obvious,and the axial force of the lower support is greater than that of the upper support.