Abstract: In order to obtain the stress mechanism of hydraulic tunnel lining under high geothermal condition, we calculated and analyzed the mechanical characteristics of a diversion tunnel in Xinjiang through theoretical calculation and ANSYS within established hot-solid coupling model. Interrelated analyses conclude that heat insulation layer between surrounding rock and concrete could obviously improve the stress situation of the primary concrete lining by reducing the average stress by about 46%, but had no significant effect on the secondary concrete lining; also the average displacement of the lining structure increased about 14%; the thermal insulation layer could also significantly improve the safety factor of primary concrete lining and secondary concrete lining, with the mean value greater than 1. The supporting system together with heat insulation layer, primary concrete lining and secondary reinforced concrete could meet the safety requirements, and can be used in practical engineering.

Key words: hydraulic tunnel lining, stress mechanism, high geothermal condition, numerical simulation, average stress, safety factor