Abstract:

There is no unified standard for the determination of the allowable ultimate displacement both at home and abroad. By analyzing the internal relationship among the pressure, internal force and deformation of the reinforcement structure, the author draws the conclusion that the structural stability depends on the load bearing capacity. Taking Taihangshan tunnel as an example, the author establishes the relationship among the internal force, safety coefficient and displacement of the reinforcement structure on basis of the monitoring data and obtains the allowable displacement of the tunnel. The method to determine the allowable displacement presented in the paper can provide reference for the determination of the allowable displacement of largespanned tunnels in special geological conditions.

Key words: reinforcement structure  , internal force  , tunnel stability  , allowable displacement