Study on variations in the coupling of train-induced air-flow and temperature in a double-track tunnel along a cold-region high-speed railway

The impact of train-induced air-flow leads to a new “transient” characteristic in the temperature field of cold-region tunnels. To investigate the variations in the coupling of train-induced air-flow and temperature in cold-region tunnels, this study, taking the Anshan Tunnel as a case study, established a 3-D computational model to examine the variations in the temperature in the double-track tunnel a-long a cold-region high-speed railway under different intervals between trains, external temperatures, and ground temperatures of surrounding rock. The influences of these factors were analyzed. The results suggest that when the interval between two trains is less than 15 minutes, its impact on the temperature field in cold-region tunnels cannot be ignored. When the interval is 15 minutes, the maximum temperature drop inside the tunnel is 1.23℃, an 8℃ increase in surrounding rock ground temperature affects the longitudinal temperature field in the cold-region tunnel by 0.03℃ to 1.95℃ per 50 m, a 20℃ increase in external temperature influences the longitudinal temperature field in the tunnel by 7.2 ℃ to 19.4℃ per 50 m, and a 1 m/s increase in external wind speed impacts the temperature field by 0.32 ℃ to 1.32 ℃ per 50 m. These findings provide theoretical support for calculating the length of the insulation layer required for cold-region tunnels.