Study On The Construction Method Selection Of Intersection Part Of City Tunnel

With the rapid development of urbanization,tunnel engineering is more and more.Intersection tunnel is a new structural form in recent years,because of the terrainconditions limit and the general line limit.It is an important subject that how to choose areasonable construction methods and reasonable construction plan on the intersectiontunnel for ensuring the safety of tunnel construction, operation and the security ofadjacent surface building.This paper bases on measured data of Chongqing JieFangBei underground parkingand connecting channel Ⅱ phase,combines with three dimensional finite elementnumerical simulation,study on different construction methods of urban intersectiontunnel and surface adjacent buildings. Mainly for the following several aspects:①The paper expounds tunnel surrounding rock deformation failure mechanismand strata deformation mechanism because of the tunnel excavation,and analyses thetwo kinds of ground deformation forecasting theory(PECK formula,random mediumtheory) commonly used by domestic and foreign scholars.②The paper makes Three kinds of different construction methods for ChongqingJieFangBei underground parking and connecting channel Ⅱ phase—Full sectionmethod,bench cut method and CRD method.③The paper simulates intersection tunnel construction with different constructionmethods by using the finite element analysis software ANSYS. Taking a comparativeanalysis about the rationality of the three kinds of construction methods through thethree aspects that surrounding rock stress after tunnel excavation and displacement ofinitial support and the settlement characteristics of the surface building. It wants tochoose the best construction methods and make a detailed construction scheme,at thesame time,it briefly analyzes the deformation characteristics of surrounding rock andinitial support structure mechanics of the branch tunnel with CRD excavation method.④Measuring the intersection section tunnel and the common section tunnelexcavation deformation,using measuring data to prove numerical simulation,analyzelaws of level convergence value and vault subsidence of intersection sectiontunnel,contrasting resemblances and differences with the the intersection section tunneland the common section tunnel at the same time.