Study on the influence of open excavation unloading construction on existing metro shield tunnels
This research investigates the influence of open excavation unloading construction on underlying existing metro shield tunnels.Focusing on an open-cut foundation pit that is adjacent to an existing metro tunnel in Jinan,this article uses midas GTS NX finite element software to carry out a numerical simulation and comparative analysis.Three factors are considered,with 28 different comparative working conditions,and the influence principles of open excavation unloading construction on existing metro shield tunnels under the influence of different factors are obtained.Based on these findings,suitable suggestions are then proposed.The results show that the angle between the open-cut foundation pit and the existing tunnel is kept at 45° or above,which can reduce the influence of open excavation unloading construction on existing tunnels.When the vertical distance between the open-cut foundation pit and the existing tunnel is above 0.5D(D=tunnel diameter),the vertical distance is more effective at controlling the uplift deformation,and when the distance is below 0.5D,the vertical distance does not have an obvious impact on controlling the uplift deformation.It is also shown that the influence of the lateral unloading area of the open-cut foundation pit on the vertical deformation of the existing metro tunnel increases linearly with the widening or deepening of the foundation pit,and the influence of the depth of the foundation pit is particularly significant.
NETL
NSTL
万方数据
维普
