Analysis Of The Influence Of Shield Tunneling On Surrounding Environment

When constructing tunnels in urban areas, the influence of shield tunneling on surrounding environment is an important issue. It has great engineering significance to find out the mechanism of the additional responses of surrounding environment induced by tunneling and seek the effective measures to control ground movements and structures'responses. On the basis of Jushu-Xilang Section of Guangzhou-Foshan Metro, this thesis studies the environmental effect of shield tunneling in complex soil strata.Firstly, when Guangzhou-Foshan Metro underneath passes through the pile foundations of Xilang Station, three-dimensional elasto-plastic numerical simulation models are established to study the tunneling-induced ground movement and deformation of adjacent pile foundations. The strengthening effects of underpinning scheme and its parametric studies are also carried out. The results show that in complex soil strata, the influence of tunneling on adjacent pile foundations is obvious and it, when necessary, could be effectively reduced by underpinning. The relationship between length of underpinning pile and settlement of existing piles is found to be nonlinear.Secondly, when Guangzhou-Foshan Metro underneath passes through the existing buildings and other structures of Zhujiang Aquatic Product Research Institute, three-dimensional elasto-plastic numerical simulation models are established by finite difference code to study the shield tunneling-induced ground movement. The results show that in the soil strata containing thick silt layer, the process of surface subsidence takes longer time and the range of influence is larger than that in the soil strata without silt layer.Finally, based on the process of Guangzhou-Foshan Metro underneath passing through existing adjacent Guangzhou Metro No. 1 Line, three-dimensional elasto-plastic numerical simulation models are established by finite difference code to study the influence of shield tunneling on adjacent railway and soil layers. It is shown that the effect of the existence of railway on lateral ground movement is greater than that on vertical ground movement.The results of this thesis can be references for tunnel constructions in urban areas.