Study On The Influence Of Shield Tunneling Under Existing Tunnel In Changzhou Metro Line 2

With the reform and opening up entering the fortieth year,the urban subway and rail transit network has also ushered in rapid development and improvement with the expansion of urban meridians.More and more cities are expanding their underground transportation networks,and new subway shield tunnels are continually emerging through existing tunnels.How to ensure the safety of the tunnel structure and ensure the normal operation of the existing tunnels under the dual constraints of engineering geological conditions and the surrounding environment,and successfully complete the shield construction method,which is a particularly important issue in the development of rail transit.Practice has proved that if the actual engineering project is carried out at the shield tunneling site,the appropriate numerical analysis method is used to simulate the numerical simulation of the shield propulsion process,and the measured data is compared with the simulated calculation results,which can be analyzed from multiple angles.The influence of shield tunnel construction on existing tunnels and the mutual influence law of shield tunnel crossing construction.The research content of this paper takes the shield tunnel of Qingyang Road Station and Dingtang River Park Station of Changzhou Rail Transit Line 2 as the background,and uses the field monitoring data to analyze the numerical calculation method by theoretical analysis and finite element simulation.The soil settlement caused by the tunnel excavation of the subway tunnel and the deformation of the existing tunnel structure are studied.The displacement of the existing tunnel lining and the settlement of the soil during the excavation process are obtained to ensure the construction of the shield tunnel.The impact of building existing tunnels is within the scope of safety control.The numerical calculation and analysis results show that when the new shield tunnel is underneath the existing tunnel construction,the texture layer of the two tunnels will be greatly deformed,and the existing tunnel and the surface will have different degrees of settlement.The construction will result in the existing The tunnel is under pressure,and there is uneven lateral displacement of the lining structure of the rectangular open-cut tunnel.The bottom of the tunnel is deformed.The maximum settlement occurs after the shield passes under the existing tunnel.Within 20m of the cross section,the stratum is disturbed by the shield construction,and it is necessary to reinforce the stratum in the crossing area.Figure[22]table[9]reference[50].