Model Experimental Study on the Cooling Measures and Effects during Construction of High Geothermal Tunnel

In order to study the cooling measures and effects in the construction environment of high geothermal tunnels and to explore their characteristics and determine the design parameters, a self-made model experimental platform was used, based on the Baoanying tunnel project in the Chengdu-Kunming railway. This platform deeply analyzed the influence of different tunnel return air velocities, fresh air initial temperatures, and different spray flows on the temperature field distribution in different cross-section positions in high ground temperature tunnels. The results show that wind speed mainly affects the initial cooling time of each tunnel section, while wind temperature mainly affects the cooling efficiency of the tunnel section. Both wind speed and wind temperature have a significant influence on the cooling rate. As the tunnel section is farther away from the tunnel face, the cooling rate and cooling efficiency will be greatly attenuated; The spray flow rate at different positions has different effects on the cooling rate, and the order of cooling efficiency from high to low is: part of tunnel basin behind nozzle > part of tunnel basin in front of air duct outlet > tunnel basin in between.