Abstract: With the development of underground engineering, high geothermal problem has become one kind of important engineering problem for deep tunnels and some tunnels with complicated geological environment. And it has attracted more and more attentions of scholars around the world. It is necessary to study the temperature distribution of the tunnel for solving the frost heaving problem of tunnels in cold regions, high geothermal temperature around the tunnel and the problem caused by tunnel fires. In this paper, a two-dimensional steady state thermo-elastic problem of tunnels is investigated by using theoretical method. The tunnel has a finite length. It is located in a high geothermal surrounding and subjected to axisymmetric temperature gradient due to excavation. The earth pressure is also considered in the analysis. The shape of the tunnel is assumed to be circle. Employing dimensionless and series solving methods of differential equations, analytical solutions of temperature, displacement and thermal/mechanical stresses have been obtained. Based on the present analysis, an illustrative example of tunnel containing the lining and the surrounding rock is numerically studied. And it is obtained the reasonable calculated thickness of the surrounding rock causing by the tunnel excavation. The conclusions provide an important theoretical basis for the thermal insulation in the tunnel construction and operation process.

Key words: tunnel, high geothermal temperature, temperature field, thermal stress field, analytical solution