Research On The Construction Technology Of Subway Shield Tunneling Across The Closely Tunnels

With the development of city underground space, there are more and more projects come out in each passing day, in which tunnels are built much close to existing tunnel. How to control the deformation, make sure the existing tunnels not be impacted while the constructing become more and more important.Based on the project of tunnel between Qibao and Jiuting in Shanghai Metro line 9, the thesis ansys the monitor datas on surface settlement,soil deformation,law of pore water pressure,tunnel rock displacement and so on.The Mindlin elastic method and 3D FEM are employed for analyzing and comparing the influence of shield tunneling on surrounding and built tunnels in different situation,construction methods,depth.In the end ,the thesis sums up the construction and surrounding protection methods in shield tunneling under shallow covering and crossing above the down line. It contains the development of construction methods, using plak to resist upfloating. This article gives advises in future construction or design.