Abstract:

To analyze the transfer and distribution of surrounding rock pressure caused by tunnel excavation, as well as internal and external hydraulic pressures acting on the rock-lining structure, a formation-structure calculation model is established using the complex function theory. The hydraulic pressure on the ring lining is simplified to a radial uniform load. An analytical function describing the interaction between the surrounding rock and lining is derived using complete contact boundary conditions, specifically, stress continuity and displacement coordination. Finally, the stress and displacement components at any position in the surrounding rock and lining structure are derived. The analysis yields the following results: (1) The radial contact stress between the surrounding rock and lining exhibits a cosine distribution, whereas the shear force exhibits a sine distribution. (2) The external hydraulic pressure reduces the effective stress between the surrounding rock and lining. (3) The action of the external hydraulic pressure partially reduces the lining tension stress zones caused by high internal hydraulic water pressure.

Key words: circular hydraulic tunnel, lining, internal and external hydraulic pressures, complex function theory, load transfer mechanism