Finite Element Analysis On Construction Simulation Of Micro Clear Distance And Shallow Buried Shield Tunnel

The development of the city and the inter-city rail is limited by the finite urban land, so the neighbourhood shield tunnel construction is more and more popular in cities. Therefore, the calculation simulation analysis of close construction considering ground conditions and the surrounding environment, by means of finite element analysis software, is the main topic of construction technology optimization and construction organization design optimization. Based on one inter-city rail, which is shield construction, established the surrounding rock-Segment Lining- close buildings 3D finite element analysis model, considering the space and shallow is increasing in the direction of the construction advance. And make Simulation and analysis of deformation and the force of the surrounding rock, segment lining, close buildings under the different shield construction process. This paper gives the following conclusions:1. This paper established the surrounding rock- Segment Lining- close buildings 3D finite element analysis model by using Geotechnical engineering finite element method. Considering the constitutive relationship of surrounding rock, Segment Lining, close buildings, the impact rules of the second tunnel made on the first one is studied by using finite element analysis software MIDAS/GTS. Calculation results of the different construction are give like ground surface subsidence, supporting structure stress changes and deformation, surrounding rock stress changes, the impact rules of the close buildings.2. The calculation considering ground surface subsidence and surrounding rock shows that, stress redistribution happened in the soil between the first and the second neighborhood tunnel. It lead to greater ground movement, the broader influence sphere and greater surface area of the settler. The maximum settlement point of the transverse settlement curve move to the second tunnel, not in the middle of the two tunnels. Subsidence on the longitudinal ground subsidence curves is increasing first and decreasing then. The surrounding rock is in a favorable stress state. The axis stress is small in arch and bottom. It increases longitudinally along the tunnel when the second tunnel is constructing. But its the stress level is low than the surrounding rock in the same depth. The maximum shear stress of each direction of surrounding rock is in a low stress level during the second tunnel construction progress and it changes little.3. The calculation considering segment stress state shows that, the rules made on first tunnel by the second is a dynamic process through the rules of stress and deformation. When shield advance but not achieve, the second tunnel is extruding or shearing the first one. When the shield leave away, the first tunnel has a little spring, because the soil unloading in the second tunnel section. Finally, it stays.4. The calculation considering the stress state of close building shows that, the close building has a good performance during the second construction process, the structure itself does not produce additional stress, because unequal subsidence between its pillars is the more uniform overall subsidence. By analysis unequal subsidence between neighborhood pillars, tilt degree, axis stress, the combination stress levels are safe.The research results of this paper provides a scientific basis, that demonstrates the optimization of relevant construction technology and process. The results can apply for relevant reference projects.