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

In recent years,the continuous expansion of the scale of my country’s cities and the rapid growth of urban population have brought urban rail transit construction into an unprecedented period of development.As an important part of urban rail transit,subway has an increasing proportion in urban rail transit.The continuous improvement of the urban rail transit network will inevitably cause the phenomenon of spatial intersection of subway lines,and the new subway tunnel will inevitably have an impact on the existing subway tunnel.For example,the shield construction of the new tunnel will disturb the surrounding soil,deform the adjacent existing tunnel structure,and endanger the safety of the existing tunnel.This paper based on the background of Qingyang Road Station～Entry Line Interval shield cross over existing main line of Changzhou Rail Transit Line 2,the mechanism of the interaction between the newly built tunnel and the existing tunnel is analyzed,combined with finite element numerical simulation and field monitoring,the deformation of existing tunnel is discussed and studied,and the corresponding control measures are put forward.The main research contents include the following aspects:(1)This paper analyzes the soil disturbance caused by the construction of the new upper-span tunnel and the mechanism of the existing tunnel,and clarify the important role of interbedded soil in proximity engineering;(2)Combined with the project of an upper span section of Changzhou Metro Line 2,conduct on-site monitoring and measurement of the impact of shield construction on existing subway tunnels,and analyze the law of surface settlement of newly-built subway tunnels during shield construction;(3)According to the actual engineering data,establish the MIDAS finite element model of this project,carry out numerical simulation of the construction process of the newly built tunnel shield over the existing tunnel,and verify the reliability of the finite element model by comparing the results of the numerical simulation with the measured data;(4)Based on the field measured data and numerical simulation results,the protective measures for the new tunnel structure and the existing tunnel structure during the tunnel shield construction process are summarized,including the establishment of risk management system,construction risk control measures,existing tunnel reinforcement measures,soil reinforcement measures and on-site monitoring measures.Figure 40 table 12 reference 50...