Research On Construction Technology Of Tunnel Portal Section Of Broken Rock Tunnel With Shallow Buried Section

With the development of economy,people frequent close,convenient traffic becomes very necessary. As a key channel tunnel of highway and railway,the construction technology directly affects the safety of tunnel construction and operation. Especially in shallow broken surrounding rock in tunnel portal section construction, due to the complex geological structure, poor surrounding rock conditions,there are many security problems. Therefore,the study of a set of adaptation in shallow broken rock portal section construction method,has become very necessary.This article launches the research through literature research, field investigation and numerical analysis method. The paper used in the construction of the tunnel construction method and construction method,analyzed their advantages and disadvantages,and adapt to the geological conditions. In the end of the West tunnel based on the project,the engineering geological condition of shallow buried tunnel in the west end,the west end of the tunnel entrance construction method and construction method of analysis. In the end of the West tunnel shallow buried portal section in the construction,compared with three step method and two side wall pilot tunnel method in the practical application of their advantages and disadvantages. The three step method and the method of double side construction scheme of the comprehensive selection. Finally,the three step method is adopted in the excavation of the tunnel portal section of the west end tunnel. The surface subsidence,vault settlement and the displacement of surrounding rock are analyzed with the monitoring measurement. And this is based on established three steps method of numerical simulation,through the data analysis results in situ monitoring and test data were compared and analyzed, to shallow buried sections of broken surrounding rock of three step construction provides guidance and applicability. The feasibility of the three step method to adapt to the construction of the tunnel portal section of shallow buried broken rock is verified. Through the research of this paper,it provides a technical reference for the excavation of the tunnel portal section of shallow buried rock.