Abstract: Deepburied tunnels in mountainous areas are often under high water pressure condition, in which seepage has a great impact on the surrounding rocks and lining structure safety. Based on the MohrCoulomb criterion, the elastoplastic analytical solution for the interaction between surrounding rock and lining structure under the action of seepage force is derived. The analytical expressions of the relations among the radius of the surrounding plastic zone, the stress and displacement of surrounding rock, and the radial deformation of lining with the support resistance are given. Furthermore, the ground reaction curve and support characteristic curve are introduced to analyze the mechanical characteristics of nonlinear interaction between surrounding rock and lining, and the radial displacement around the cave is obtained by the convergence constraint method. Subsequently, relying on the deepburied section of the Niuheling tunnel, the accuracy of the theoretical analysis method based on the MohrCoulomb criterion recommended is verified. Finally, the parameter analysis is performed on the relationship between the support resistance, the plastic radius, and the radial displacement around the cave. The main results show the following. (1) An increase in the support resistance can effectively limit the development of the plastic zone and the radial displacement around the cave. The initial limiting effect is obvious, and the subsequent effect gradually decreases. (2) The plastic radius of the surrounding rock and the radial displacement around the cave show nonlinear growth with the increasing seepage water pressure. (3) In the case of a certain radius of the plastic zone, low permeability lining can reduce the required support reaction force and radial displacement around the cave. The research results can provide a certain theoretical basis for the design and construction of tunnels in waterrich mountain areas.

Key words: waterrich mountain tunnel, deepburied tunnel, interaction between surrounding rock and lining, MohrCoulomb criterion, seepage force, elastoplastic analytical solution