考虑裂隙及相变影响的寒区隧道温度演化研究OA

[Objective]Freezing damage occurs during the construction and operation of tunnels in cold regions,which seriously threatens the structural safety of tunnels and traffic safety.To solve the freezing damage problem,it is necessary to determine the distribution patterns of the tunnel temperature field and the extent of freezing damage in the surrounding rock.The random distribution of fissures in the surrounding rock and the water-ice phase change inside fissures are important factors affecting the two.[Methods]By introducing enthalpy into the bond-based peridynamics heat conduction equation,a numerical model considering both fissures and the effects of water-ice phase transition was constructed to describe the energy transformation process during water-ice phase transition in fissures of the surrounding rock.The accuracy of the model was verified using the analytical solution of a tunnel in homogeneous cold regions and the COMSOL numerical solution for a single-fissure rock mass.Random fissures were introduced based on the Monte Carlo algorithm to analyze the influence of different fissure parameters on heat conduction.Taking the Yuximolegai Tunnel in Xinjiang as an example,the random fissure parameters of the surrounding rock model were estimated using field temperature monitoring data,and the temperature field patterns of the tunnel in cold regions under freeze-thaw conditions were investigated.[Results]The results showed that the proposed model effectively solved the water-ice phase transition problem and accurately determined the position of the phase transition interface through comparison with theoretical and numerical solutions.Without considering water migration,fissures had a hindering effect on heat conduction,and the hindering effect enhanced with the increase in fissure density,length,and aperture.The influence degree followed the order of fissure density>fissure length>fissure aperture,while the fissure angle had no influence on heat conduction.The temperature and freezing depth of the surrounding rock around the Yuximolegai Tunnel in Xinjiang both exhibited periodic variation.With the increase in freeze-thaw cycles,the temperature of the surrounding rock showed a decreasing trend,while the average freezing depth showed an increasing trend.Meanwhile,the extent and evolution of freezing damage in the surrounding rock at different times were determined.[Conclusion]The research findings have guiding significance for the study of temperatures field in tunnels located in cold regions.