Research On The Deformation Control Of The Shield Tunnel Under The Existing Channel

With the rapid development of cities and the continuous expansion of rail transit network,the spatial relationship between tunnel and underground buildings has become increasingly complex.Double-line parallel tunnels have appeared successively in rail transit projects in major cities through existing underground buildings or underground pipelines.In the process of shield tunneling,the ground loss caused by shield tunneling causes the change of soil displacement,which may lead to cracking or even collapse of existing buildings.Therefore,when shield tunneling passes through existing buildings,its influence on existing buildings should be effectively controlled.In this paper,the settlement of existing tunnel caused by shield tunnel Underpassing existing tunnel is analyzed based on the research background of Nanchang Metro Line 2 shield tunnel Underpassing existing tunnel.Firstly,by analyzing the influence of shield tunneling on ground surface and existing tunnel settlement under different working conditions,the main settlement range and settlement law caused by shield tunneling are obtained;then,the settlement of existing tunnel bottom before and after reinforcement is analyzed,and the effectiveness of reinforcement measures is obtained;finally,by comparing with field monitoring results,numerical simulation data and real-time monitoring data base are obtained.This is consistent.This study can provide some reference for similar projects in the future.The main research contents are as follows:Deformation and Settlement Analysis of Shield Tunnel Crossing Existing Passage.Three-dimensional finite element method is used to simulate the construction process of shield tunnel passing through existing channels.Firstly,by adjusting the balance pressure of the silo,the influence of surface settlement under different equilibrium pressure of the silo is analyzed,and the suitable balance pressure of the silo is obtained.Then,on this basis,the deformation characteristics of the existing channel and soil body are analyzed.Design and analysis of reinforcement schemes for shield tunnels passing through existing tunnels.The reinforcement design scheme for shield tunnels passing through existing tunnels is proposed,and the calculation and analysis after reinforcement are carried out.After the reinforcement of the existing passage and surrounding soil,the deformation of the existing passage and the settlement of the soil above the existing passage can be effectively reduced,and the deformation of the segment lining under the existing passage can be well controlled.Automatic monitoring and analysis of shield tunnels passing through existing channels.The existing automatic monitoring scheme for shield tunneling is put forward,and the measured points are arranged in the field.The settlement data obtained from the measured points are compared with the numerical simulation results.Through the analysis of the measured data,the whole construction process can be effectively monitored,and the rationality and accuracy of the calculation model can be verified.The research in this paper can provide some reference value for similar engineering applications in the future.