| National economy which is developing quickly needs the higher grade of road, the super-span road tunnels are appeared gradually. Along with increase of span, difficulty and risk of tunnel engineering will increase rapidly. Strictly speaking, the current codes can only guide design and construction of the tunnel under three-lane tunnel project. The super-span tunnel is still at initial stage. Therefore, aiming at the super-span road tunnel, systematic advanced research has important theoretical value and actual meaning.By numerical simulation, indoor model test, monitoring in site, reliability theory, linking to the practice in Hanjialing tunnel, some research works were done about excavation scheme and stability of super-span road tunnel.Reasonable section of super-span road tunnel was selected, the reasonable tunnel lining section was obtained. By numerical simulation on various span road tunnels, the difference was educed about mechanics behavior between super-span tunnel and general section tunnel. Aiming at study of various excavation methods of super-span tunnel, the reasonable construction scheme was given.By various construction schemes and various loop footage, the 3D numerical simulation was conducted, time effect and space effect of surrounding rock and supporting structure in construction were opened out. The relation between trace area and stability of surrounding rock was built. The efficient construction measures were given.Aiming at various construction methods of super-span road tunnel, The indoor model test was conducted. Surrounding rock deformation effect in construction of non-suppoting tunnel was simulated. Displacement rules and final failure modes in various construction methods were .obtained, efficient excavation scheme suppoting mesures were put forward. The conclusions of numerical analysis were more confirmated.Monitoring works in site of super-span road tunnel were elaborated. Supprting lining references of design were validated. Bolt rational length at three grade of stratum was given. Distribution rules of axial strain of bolts, most strain and most stress were obtained. It has more reference value for tunnel in site.Security during the period of servings should be aimed. With a view to randomicity of various factors, the reliability analysis of lining structure of super-span road tunnel was developed. Relative significance of various uncertain factors was given to inner force of section. Most important factor of influence on safety in construction was unveiled. The reliability indexes of tunnel structure in site were computed and analyzed.Study in this thesis contain many aspects of mechanics behavior of super-span road tunnel, such as structure scheme choice, mechanics behavior simulation in construction, influence of trace area on stability, indoor model test, monitoring in site, and reliability analysis. Works are systematic and complete. It can provide reliable technic guarantee for design and construction of super-span tunnel in site. Research idea and method have importance for similar big-span tunnel engineering.
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