Research On Characteristic Of Structures Support And Synergistic Effect In Tunnel Project

In the 1950s,the theory of the new Austrian excavation tunnel was put forward,and it was widely used in tunnel project at home and abroad.However,as the geological situation became more and more complicated,the size of the tunnel cross-section becomes larger.The tunnel support system composed of lining,bolting and steel frame supporting structure need to be ensured the safe construction of the tunnel.Whether it can effectively control the deformation of the surrounding rock of the tunnel,and whether the function of these supporting methods is used to the full is important to structural safety of tunnel and formulating a cost-efficient scheme.In view of the above problems,this paper research on the supporting characteristics,synergistic mechanism and supporting effect of lining,bolting and steel frame supporting on the basis of the background of five-mountain tunnel in Zhenda Road.The main contents are as follows:(1)Reviewing the development process and main problems of tunnel engineering.Analyze the new Austrian law especially,which plays an important role in this process.Summarize the existing development of supporting theory.(2)Studying on the supporting mechanism of lining,bolting and steel frame supporting structure.Analyzing the energy change during tunnel excavation,the load condition of each support form,Interaction between support form and surrounding rock.The relationship between the supporting effect and the size of the supporting structure is deduced to further study the synergistic effect of the various supporting structures.Accompanied with the numerical simulation of simple cross-sectional shape tunnel,the mechanism of the three structures and the surrounding rock condition are summarized.(3)Using FLAC3D software to establish the numerical model of the five-mountain tunnel in Zhenda Road.The new Austrian method(CRD method)was used to simulate the tunnel excavation process and lining,bolting and steel frame were applied.From the aspects of stress field,displacement field of the surrounding rock,this paper focuses on the vertical displacement of vault and floor,and horizontal displacement of side walls.Finally the advantages and disadvantages of supporting structures are obtained.(4)Summarizing the supporting characteristics and the conditions of lining,bolting and steel frame,and provide some guidance and technical basis for the construction of the five-mountain tunnel in Zhenjiang Road.At the same time,it provide reference for the selection of supporting measures and construction methods of soft rock tunnel,so as to make the best supporting scheme according to geological conditions.