Study On Ground Subsidence Caused By Shield Construction Of Double-line Tunnel For Underground Pipe Gallery

From 2013 the State Council issued a document presented to the pilot construction of underground pipe gallery has comprehensive pipe gallery construction scale continues to increase.In the course of the construction of the tunnel,the former single line tunnel form cannot meet the needs of the comprehensive corridor construction.In consideration of other factors such as cost and other factors,more and more comprehensive tunnel and subway tunnels are no longer construction of single line tunnel,and the double line tunnel is adopted.The domestic and foreign scholars have studied the ground settlement of tunnel shield construction,including empirical formula method,theoretical analysis method,model experiment method and numerical analysis method.The research theory of ground subsidence caused by tunnel construction by shield method is based on the construction of single line tunnel,and the analysis of the shape of the cross section of the double line tunnel is less.Because the adverse effects of double track tunnel on the soil will be superimposed,which will cause large surface deformation and settlement.Further,it is necessary to further analyze the ground deformation of double line shield tunnel construction.The transverse section of the underground tunnel construction in Shenyang underground pipe Corridor project is a double line tunnel with left and right 12 m.This paper takes the Shenyang underground pipe Corridor project as the background.Through the analysis of monitoring data and the numerical simulation of MIDAS,the law of the ground deformation effect of the double line shield tunnel construction to the surface deformation is studied and analyzed.The main research and analysis work is as follows:(1)To deal with the lateral monitoring data of 4 groups of phenomena in the Shenyang tunnel construction,the surface deformation caused by the construction of the double line shield tunnel in Shenyang tube corridor is analyzed from two aspects,such as the shield parameters,geological conditions,and monitoring schemes,etc.,from the single line and the double line.It is found that the ground surface subsidence caused by the construction of the single double line tunnel in this project is generally characterized by positive distribution,and can be modified and estimated by the Peck formula.(2)The correction of the Peck formula.According to the law of processing and analyzing the measured data in the engineering field,the discrete measured data are regressed and the correction coefficient of the related parameters in the Peck formula of the Shenyang tunnel construction single line tunnel is calculated.Through the superposition principle,the revised Peck formula after the construction of the single line tunnel in Shenyang tube corridor is used to get the revised Peck formula of the Shenyang tunnel construction double line tunnel,and the formula is proved to be reasonable and reliable.(3)Combined with the actual engineering data of tunnel construction in Shenyang,MIDAS software is used to simulate the work process of shield tunneling in double track tunnel.By comparing the simulated results with the field measured data and the revised Peck formula,the reasonable reliability of the modified classical Peck formula and the three-dimensional MIDAS model in the construction of the tunnel construction in Shenyang tube corridor is verified.At the same time,the influence of the elastic modulus of soil,grouting pressure,and the supporting force of the excavation face on the surface settlement caused by the double line shield tunnel is analyzed,and the constructive suggestions are provided for the future design and construction.