The Mechanism And Control Of City Subway Tunnel Cross Interaction

After 30 years of reform and opening up,the economy obtained the rapid development of our country;the course of urbanization dominated by the government deepen increasingly;available space in city is exceedingly little,which enable us to explore new development space.Hence the use of underground space gradually become the new trend of urban construction nowadays,of which the best way to ease urban traffic pressure is building urban rail transit system. Along with the increasing urban subway construction line,however,there will be an interpenetrating subway tunnel bringing about series of problems in the process of near cross tunnel construction,which enable us to make further research and analysis concerning adjacent cross tunnel project.This paper take Hefei metro line 1 beneath and passing through line 5 as engineering background,and deduce the general pattern about left line of Hefei metro line 1 in near interpenetrating tunnel construction by means of analyzing theoretical calculation,numerical modeling and monitoring data.My work is as follows:(1)Comprehensively elaborate research background and significance of this thesis,and summarize the problems existing in the research plan and the content as well as structure of this paper on the basis of the view of the research of the stability of surrounding rock and the current situation of crossing tunnel.(2)Using the theory to analyze the principle of the near tunnel surrounding rock stress.According to boundary conditions and formula of force in the book subsurface structure written by Sun jun,an academician from Tongji university,I calculate and deduce the analytical solution of radius of plastic range.Then summarize the changing condition radius of plastic range followed by the changes of c and ? through observing the parameters c and ? taking different values.(3)According to the actual construction conditions, the numerical calculation model was established using finite element software, through numerical simulation to calculate the tunnel surrounding rock plastic zone analysis, comparison of different soil parameters under the tunnel surrounding rock plastic zone, analyzed the variation of intersecting tunnel under different conditions of axial force and displacement of the segment and comparative analysis of calculation results, verify the rationality reinforcement measures, finally establish the model according to the actual conditions, according to the needs of the engineering acquisition of vertical displacement and ring tunnel stress data processing;(4)Dealing with the data of field monitoring,study the interact influence of the process of multi-line interchange tunnel approaching excavate through contrastively analyzing the results of MIDAS/GTS numerical modeling actual working conditions and field test data,which provide a theoretical foundation for intersecting tunnel construction.