YoThermocouples have limitations in accurately measuring the temperature of discrete points within a tunnel as they fail to capture the continuous temperature field of the tunnel In contrast infrared

In summary, while thermocouples have limitations in measuring the temperature of discrete points within a tunnel, infrared thermography can effectively measure the continuous temperature field of the tunnel surface. In a fire test, the outer surface temperature of the tunnel was monitored using infrared thermography, and analysis revealed that the temperature in the cracked area of the ceiling increased significantly while the temperature in the uncracked area remained notably lower. This observation, combined with macroscopic observations of concrete cracking during the fire test, enabled the identification of the distribution of the primary cracks on the outer surface of the tunnel