The Mechanical Behavior Of Large Cross Section Tunnel Construction

In recent years, with the development of our country’s economic construction and the acceleration of urbanization, increasing demand for infrastructure, especially transport infrastructure construction, the large cross section tunnel seems very demandin, increasingly large scale. The construction of the large cross section tunnel can not only perfectly meet the requirement of special geologic and topography, more flexible cohesive ways of permanent way and bridges with tunnels, the special requests for overall route line-type, but also conducive to the schedule and optimize for overall route line-type.The tunnel engineering is excavated extra-large cross-section and low flat-ratio road tunnel in the condition of having tunnel, so division excavation method is adopted. The surrounding rock was inevitably disturbed frequently, the status of tunnel structure was very complex, which were obviously space effect.Firstly, this paper studies the deformation of Three-dimensional finite element analysis process by the use of ANSYS software with Durcker-Prager yield criterion. This paper studies the deformation of division excavation method at different stages and concludes the stability and stress state of the support structure and wall rock during construction. Study found that the tunnel vault and the arch part of that is stress concentration surrounding area, most likely in this damage occurred.This article analyze spatial distribution features of the initial geostress and basic mechanical properties of rock mass in the large-section tunnel; strain and stability of tunnel wall-rock sector; distribution of stratum displacement and the evolution rules of primary support.