In order to address on the high-geothermal issue of the power tunnel of Bulunkou-Kongur hydropower station, an analytical method was first used to evaluate the temperature distribution and mechanical characteristics of surrounding rock and lining structures of high temperature tunnel. The transient analysis was applied to study the temperature distribution and the results showed that the temperature distribution was strongly related with the heat transfer and thermal conductivity coefficient. The steady-state method was used to validate the obtained temperature distribution and to further investigate the mechanical characteristics of high-temperature tunnel. The stress of high-temperature pressurized tunnel can be divided into three parts and the percentage of each of them in the coupled stress was also given. A high tensile stress in the circumferential direction was observed in the surrounding rock as well as the lining, subjected to the coupled effect of the temperature load and the internal water pressure.
With the implement of western exploitation and 12th 5-year plan, the economy construct in western regions of China enter into a new development period. Many large scale projects have been or will be located in the active areas of modern tectonization, which is unavoidable to meet high geothermal problem. Understanding the temperature distributions and stress characteristics is important in the design and construction of high-temperature tunnels. Although there are many numerical models for modeling high geothermal, analytical solutions are still desirable in direct applications or in the validation and verification of numerical models. Lu (1985) discussed the method for stress analysis of prestressed grouted concrete lining and surrounding rock in hydraulic pressure tunnels under various load conditions, and analyzed lining and its surrounding rock based on the plastic hardening theory. Besides, Hou (2001) analyzed the application conditions of surface force theory and physical force theory by comparison of the calculation results and considering the engineering practice. Dimitrios (2007) presented an analytical expression for the estimation of the steady state groundwater ingress into a drained tunnel of circular cross section on the basis of conformal mapping. Feng (2007) and Chen (2008) have studied the stability of Jinping II Hydropower Station. Hu (2009) presented an analytical solution for the determination of internal forces of a jointed segmental precast DOT lining.