| When the foundation pit project is constructed,nearby buildings,pipelines,tunnels will be affected.When constructing deep foundation pits near subway tunnels,it is more necessary to strictly control the deformation of foundation pits.By controlling the pit deformation,can effectively reduce tunnel deformation.Safe operation of the nearby tunnel will be affected foundation pit project is constructed,and the calculation theory of such effects is still in the development stage.Therefore,this thesis take the foundation pitted of Dongguan city as an example,combined with the MIDAS GTS NX numerical analysis software,the simulation was carried out to explore its influence on the nearby tunnel.The following main conclusions are drawn through the subject research:(1)Introduction to the main types of foundation pit support.It analyzed its deformation and ground settlement when the foundation pit was excavated.When the foundation pit is excavated,analyzed its influence on the deformation of adjacent tunnels and its calculation method.(2)For this deep foundation pit project,Lizheng software was used to design the scheme to ensure the safety of the supporting structure and reduce the impact on the surrounding environment.The overall stability is 2.635,Anti-overturning stability is3.919,which proves that the entire supporting scheme is safe and feasible.(3)After comparison of numerical simulation and monitoring data,the horizontal displacement direction of the tunnel always points to the direction of the foundation pit.The vertical displacement direction of the tunnel changes with the relative height difference between the plane depth of the excavation bottom surface and the tunnel axis.When the plane depth of the excavation bottom surface of the foundation pit is higher than the tunnel axis,the tunnel will move upward,otherwise,the tunnel will move downward.(4)Maximum horizontal displacement is 4.757mm(foundation pit direction),maximum vertical displacement is 0.922mm(upward direction).These meet the safety requirements for normal use of the subway lines.(5)To study the tunnel reinforcement method and limit influence distance of excavation.By modifying the strength and the embedded depth of the supporting structure,the geotechnical parameters of the location of the tunnel,and the distance between the two,the influence of earth excavation on the deformation of the adjacent tunnel is studied.For projects with similar engineering conditions,can refer to the relevant research results in this article. |
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