Construction Mechanics And Monitoring Measurement Of Large-span Multi-Arch Tunnel

This thesis discussed the key construction techniques of large span arch-tunnel. Based on Shatangkeng tunnel of Guangzhou-He Zhou highway and research status of large span tunnel and arch-tunnel, through monitoring measurement and numerical simulation, this thesis studied construction mechanics of large span arch-tunnel, and have received the following main results.--Based on summarize of the investigation and the engineering experience, it influenced several major issues on the mechanical problems of large span tunnel construction, and put forward the commonly used research methods and principles.--This thesis introduced the research status of large span arch-tunnel and project overview of Shatangkeng tunnel. From the characteristics of the tunnel structure, the status and role of measurement monitoring in NATM construction, it concluded the importance of dynamic monitoring in courses of tunnel construction, and introduced the contents of monitoring measurement and commonly used methods of monitoring data processing comprehensively.--By system analysis to monitoring measurement data, this thesis got its main rules and characteristics, and analyzed the possible causes of poor regularity of the monitoring data. In order to get the law of displacement deformation, regression analysis was used in simulation and trended forecasting of s-t curves.--The dome sinking data of K48+422 section were analyzed by Gray Forecast Model, and compared with the numerical simulation results on vaults sinking of the V-rock, it concluded that, the construction method was reasonable and disturbance to the rock was smaller, meeting the mechanical requirements of construction.--Based on Three-Dimensional elastoplastic finite element analysis to construction mechanics of Shatangkeng tunnel, this thesis showed the mechanical condition of construction stages. It showed that, the shear stress at arch feet was greater than the allowable stress of concrete; the sportsmen at arch feet should be strengthened. And the secondary lining played an important role in reducing stresses of the rock, center pillar and early retaining structure, it should be applied timely.The conclusions of this thesis can be referred by construction of large span arch-tunnel.