Study On The Construction Technique Of The Two Way 6 Lanes Twin-Arch Tunnel With Hollow Center Pillar

In recent years, along with the construction and develop of high speed, high quality expressway and highway traffic transport amounts increased rapidly, and the urbanization processes' acceleration, the two-way 4 lanes twin-arch tunnel cannot satisfy the increasingly growing of traffic requirement, particularly in special geology and topography zones. Therefore, in the condition that the circuit parts inconveniently, the two-way 6 lanes can be use as the alternative plan to set up the traffic rate.The paper studies on the construction mechanics, with the background of Nanjing inner channel' s Jiuhuanshan mountain twin-arch tunnel. In different terrain conditions and tunnel depths, 2-D and 3-D finite elements method (FEM), was applied to analysis the hollow center pillar. The paper' s research findings work straight with the project practice, and can be guidance to similar projects. It also has reference value to make codes.Firstly numerical simulation was used to analysis the hollow center pillar' s structural design , so the load and the formula then was gained, the main factors that influence the pillars' stability and the stresses in the pillar and the construction techniques are also analyzed. Secondly, after fully investigate and research, construction methods and structural design along with qualitative analysis and quantitative analysis optimization are the two aspects to optimize the twin-arch tunnel design. Thirdly, the tunnels long-term safety performance is analyzed and evaluated by load structure method and ground structure method. Fourthly, the conclusion was reached by 3-D elastic and plastic numerical simulation to the tunnel' s spatial effect.