Study of thermo-mechano-damage coupling behavior of surrounding rock of deep tunnel

Based on the theories of thermo-mechanics and elastoplastic mechanics, the thermo-mechanical coupling effects of rock and their effects on mechanical and thermal parameters are analyzed. By defining the evolution equations of thermo-mechanical coupling parameters under the damage of temperature effects and mechanics, a new coupled thermo-mechanical damage model with improved Mohr-Coulomb criterion is established, and the numerical implementation in ABAQUS is given. Using finite element method, a typical example was given to verify the importance of the thermo-mechanical fully coupling of rock. Taking a deep tunnel of clay stone as background, the evolution and distribution of damage, temperature and coupling parameters of the surrounding rock are simulated in detail. The results show that the temperature has a great influence on rock properties and damage evolution. Also, the damage by excavation and thermal stress has a great influence on conducting and diffusing of heat. The proposed model can depict the excavation damage, control heat circle and coupling parameters evolution, and may provide a new tool for associated applications.