Research On The Influence Of Shield Tunnel Adjacented Toexcavating Foundation Pit

With the city developing,subway route is more and more concentrated.As the city excavation of foundation pit engineering environment becomes more complex, it often closes to the existing subway tunnels underground. The excavation of foundation pit often makes a certain adverse effects to the shield segment. Excavation iMPacts to study and master the operation mechanism of shield tunnel, that is to be studied and solved, and it has a very important practical significance.First, orthogonal experimental method is used to research the sensitivity of three factors to the tunnel deformation:space between foundation pit and tunnel, the depth of foundation pit, and top displacement of envelope pile. Sensitivity of horizontal deformation caused by the selected three factors on the tunnel, from strong to weak, is following:the depth of excavation>space between excavation and middle line of tunnel>displacement of envelope pile. Sensitivity of horizontal deformation caused by the selected three factors on the tunnel, from strong to weak, is space between excavation and middle line of tunnel> displacement of envelope pile >the depth of excavation. Sensitivity of tunnel bottom deformation caused by the selected three factors on the tunnel, from strong to weak is space between excavation and middle line of tunnel >the depth of excavation> displacement of envelope pile.In addition, FEM is used in this article to investigate the effect of above three factors on lining deformation. As the depth of foundation pit increases, the less horizontal displace ment of lining and the less amount off loat upward of lining are obtained when the excavation depth of foundation pit does not beyond the buried depth of crown of lining; The horizontal deformation of lining increases rapidly and the crown of lining start to settle when the excavation depth of foundation pit beyond the buried depth of crown of lining. When the spacing between foundation pit and adjacent tunnel over 20m, excavation of the tunnel effect is very small, that can meet the specification requirements. Tunnel pile retaining structure horizontal displacement and the moved roughly into three power relationsAt last, take one project as an example to carry out the simulation: the influence of Shenyang Central Plaza excavations on the near shield tunnel, this verifies the correctness of the conclusions of this article to provide reference for similar projects in Shenyang...