Research On Stability Of Surrounding Rock And Mechanical Of Middle Rock For Small Spacing

Due to complicated topographical and geological conditions as well as large numbers of mountainous areas, constructions of high-grade highway unavoidably meet with lots of tunnel works. As a result of special geological and topographical limitations, space of tunnels cannot satisfy with general technical codes. Therefore, such special structure shape as small spacing tunnel, twin-bore tunnel should be applied.Aiming at twin-bore tunnel with small spacing, this paper applied 2D and3D FEM numerical analysis the construction the adjacent formation stability and centerquestion and so on band mechanics behavior has launched the research. Firstly, the plane elastoplastic model of Yinjiayan twin arched-tunnel has been set up . Then, the paper introduces DP (Drucker—Prager) surrender criterion of rock soil project adopted and basic step of the tunnel level analysing systematically. Through calculating Lead holes and excavate it to the displacement field of country rock and influence in conformity with the force field while understanding , fix to monitoring and controlling the position where the danger with very key work is lighted, and have got some useful conclusions, have offered data-prepring for the fact that all the section is excavated on main hole of the tun.The paper at first studies on the stability of tunnel with no support by 2D FEM and draws the conclusion of what are the main factors effecting the it, stress distribution of surrounding rocks and deformation characters of middle rock pillars. Then excavated the analogcomputation through the plane to depend on project nine ranges small spacing tunnels three to have the representative significance theadjacent formation cross section, obtained it to excavate in theprocess the displacement and the stress field, support the structurestress condition, as well as tunnel excavation completed after thefinal plastic area. Has provided the certain instruction for nineranges tunnels design and the safe construction.by the study on 3D-excavation of twin-bore tunnel with small spacing especially for stability of middle rock pillars, the paper clarifies the interaction of twin-bore tunnel with small spacing and gives the reasonable interval between the cutting faces.The paper takes design & implementation of construction measurement of jiuling tunnel as its basis. Based on the gathered data of esperimence, the feed back according to stability analysis of FEM are conducted so as to grasp the rules of deformation and the stress of ground ang structure . By analyzing the pressure data of some sections, and compared with the finite element result, has confirmed the finiteelement analysis result.Finally, it summarizes the feasibility and the meaning of FEM analysis and various kinds of experience method in Observational Method construction. The research results have been offered for jiuling tunnel construction and guided effectively.