Abstract: To obtain the boundary conditions for coupling thermo-mechanical simulation of underground caverns for compressed gas storage, based on the mass and energy conservation equations of compressed air, a calculation method for the solution of thermodynamic process analysis of compressed air and determination of boundary conditions of coupling thermo-mechanical simulation was proposed in software FLAC3D. The calculation method for thermodynamic process analysis of compressed gas was also validated by an example cited in the paper. The variation characteristics of boundary conditions acting on the cavern wall under the situation of charging and discharging were explored with numerical simulation method. The influences of the initial temperature, the convective heat transfer coefficient and the thermal conductivity of the surrounding rock on the boundary conditions of the cavern wall were also analyzed. The research results show that the boundary of mechanics and heat transfer analysis of underground gas storage cavern has a remarkable dynamic change during operation, which is closely related to the state of compressed air, the heat exchange characteristics of cavern wall surface and the heat conduction characteristics of surrounding rock.

Key words: compressed air energy storage, underground rock cavern, coupling thermo-mechanical analysis, boundary conditions