Analysis Of Surface Subsidence Caused By The Nanchang No.1Metro Line

With the continuous expansion of the city size, serious traffic congestion has beenhappened in many cities. And then a trend of the subway development has been created.The subway tunnel excavation will inevitably produce surface movement anddeformation. Too much ground movement will do serious harm to the ground buildingsand underground pipelines. Domestic and foreign scholars have done a lot of work onthe surface movement and deformation caused in subway construction. And certainresults as methods from two-dimensional to three-dimensional or from the theoreticalanalysis of the finite element simulation have been achieved.By collecting and reading lots of related literature and data, the author has done anin-depth study of surface subsidence caused by tunnel in this paper. First on the base ofthe existing research study, the surface subsidence mechanism, influencing factors ofsurface subsidence and the characteristics ground settlement are analyzed. The lateralsurface subsidence caused by tunnel excavation is analyzed theoretically in this thesis,and the stochastic medium theory calculation of surface subsidence caused by tunnelexcavation is discussed in detail. Then the calculation formula of surface subsidence issimplified. The simplified formula can be more practical, it can consider the effects ofdepth separately and only need to consider two parameters--the impact angle andequivalent ground loss parameters. Based on the subway project (phase) in Nanchang,this article introduces measures to control the settlement and the real-time monitor oftunnel excavation. The numerical results of the lateral surface subsidence caused bytunnel excavation were obtained by using the simplified formula. And then three-dimensional finite-difference software FLAC3D was adopted for the simulation ofsurface subsidence caused by tunnel excavation. Finally, the calculation value is closerto the numerical simulation results and the measured data. It might be seen that thesurface subsidence can been calculated correctly by the simplified formula based on theappropriate parameters.