Abstract:

Due to the development of transportation works in China, more and more deep tunnels are built in high geotemperature environment. Geotemperature has influences on the stress characteristics and durability of the lining structure of tunnels. However, in China, few researches have been made on the mechanical behavior of deep tunnels in high geotemperature environment. The stress characteristics and the stress variation tendency of different parts of the lining structure under different temperatures are studied by means of indoor model test, with Gaoligongshan tunnel as an example. Conclusions drawn are as follows: 1) Internal force redistribution will emerge as the geothermal temperature creeps up; The axial force of the lining structure increases linearly as the temperature increases; Generally speaking, the bending moment of the lining structure does not change significantly，while the bending moment at the tunnel crown decreases as the temperature increases and the bending moment at other positions shows the opposite tendency; 2) The arch feet of the lining structure are seriously affected by the temperature, therefore much attention should be paid to the arch feet in the design and construction of the tunnel; 3) Due to the effect of the temperature load, the safety margin (safety coefficient) of the lining structure is significantly reduced. These conclusions can provide reference for the design and construction of similar projects in future.

Key words: tunnel, high geotemperature, lining structure, model test, stress characteristics