Research On Construction Technology Of Shield Section Of Existing Subway Lines On Shallow Overlying Soil

With the large-scale construction of urban subways,the newly constructed subway tunnels and existing subway tunnels will intersect,and it is necessary to climb up or down the existing lines,especially for tunnels with close distances,in design and construction.It is more difficult.This paper relies on the Tianjin Metro Line No.4 line project,for the structural deformation of existing lines,using structural calculation methods,using Midas/GTS engineering calculation software for engineering modeling,the structure under different working conditions According to the analysis,it is found that under the two working conditions,the floating amount of the No.3 line during the construction of the No.4 line is within the allowable range,and the working condition 1 is relatively small,because the shield well of the No.3 line is reinforced by the freezing method.The coiled tubing is not removed,so a 1.45 m spacing is recommended in this scenario.Combined with the above calculation results,this paper studies the shallow shallow soil excavation scheme,the protection of the existing line 3,the protection of the underground pipeline,the initial reinforcement of the shield and the anti-floating effect of the section.Calculate the feasibility of the results.In order to monitor the possible problems in the process of shallow overburden excavation on the shield line,in order to monitor the dynamics of the surrounding rock,supporting structure and the displacement of the building in the construction process,the monitoring and measurement design was carried out to ensure the construction.Simultaneously with monitoring.