Study On Construction Mechanical Behavior Of Large Span Arch-tunnel

With the development of highway construction in China,large span arch-tunnels are being widely used as a feasible structural form.Due to the complex section form,themechanical behaviour of the surrounding rock and the supporting structure of a twinarch tunnel is more complicated than one of a single arch tunnel.At present, this thesis studied construction mechanics of large span arch-tunnel has become a focus task in engineering.The thesis depends on the research project " the key construction techniques of large span arch-tunnel. ", Based on Shatangkeng tunnel of Guangzhou-He Zhou highway and research status oflarge span tunnel and arch-tunnel,through this studied construction mechanics of large span arch-tunnel and The focus of analysis is on the influence of the unsymmetrical pressure on construction steps and have received the following main results.Firstly, Based on Two-Dimensional elastoplastic finite element analysis to constructionmechanics of Shatangkeng tunnel,this thesis showed the mechanical condition of construction stages.It showed that, maximum displacement occurred in the vault department, the dome subsidence is much greater than the level of convergence, the smaller side-wall displacement the shear stress at arch feet was greater than the allowable stress of concrete.Secondly, By analyzing the unsymmetrical pressure of large span arch-tunnel construction methods with arch features made the first excavation of shallow side of the program than the first excavation of buried at the side of the program is more reasonable, theoretically confirmed the the unsymmetrical pressure of large span arch-tunnel construction sequence is feasibility and effectiveness.Finally, The conclusions of this thesis can be referred by construction of large span arch-tunnel.