Research On The Influence Of Shield Tunnel Construction Impact On The Strata And Adjacent Bridge Pile

Shield tunnelling method is widely used in the construction of urban metro in the soft soil because of its special advantages. During the tunnelling work, the disturbance to the soil and the effect to the nearby buildings are the focus subject at all times. The analysis of the ground settlement and its development can predict the problems in the building course and guide workers to adopt effective measures, so the research is significant for practical engineering.This paper takes one section in the first stage construction of the Beijing Subway Line6, TIANSHUIYUAN Station to SHILIPU Station, as project background. It researches the tunnelling effects to the soil’s deformation, and especially analyses the risk engineering-the tunnel passing through Honglingjin Bridge. The research method we adopt is using finite element software MIDAS/GTS to model the tunneling course in the form of elastic-plastic model. The main research contents are as follows:(1)This paper analyses the basic laws of the tunnelling effects to the soil and the nearby buildings, and also illustrates the mechanism of the ground settlement and the influences of the construction factors.(2)This paper simply introduces the techniques and steps in the shield tunnelling. On the basis of the principles, it adopts finite element software to model tunneling more accurately.(3)Using the basic theory of FEM and reasonable elements, this paper compares three3D models in which main factors such as grouting pressure, pushing force, the surface between piles and soil, and the hardening of grout are taken into account, and secondary factors are eliminated.(4)With the results of the numerical analysis, this paper puts forward corresponding construction measures to insure the security of the structures. This paper also specifies how to carry out the monitoring alternatives. The analysis of the monitoring data illustrates that the settlement is kept within a reasonable range. Because the measures are suitable, the construction meets the security requirements.