Simulation study on heat transfer between underground adjacentparallel precision constant temperature tunnels

The heat transfer between tunnels during the operation of three adjacent tunnels in a large scientific project is studied, and the differences in heat flux density of tunnel envelopes and surrounding soil temperature field under single tunnel operation, two tunnel operation and three tunnel simultaneous operation modes are analysed. The results show that the heat flux density under all operation modes drops significantly in the first month, which can reach more than 90%. The heat flux density under different operation modes exhibits significant differences after six months, the maximum value is about 115% of the minimum value, and the maximum heat flux density can reach 268% of the minimum value after 10 years. When the number and sequence of tunnels in operation are different, the heat flux density attenuation is different. The more the number of tunnels in operation and the closer the distance, the greater the mutual influence, and the lower the heat flux density of the envelopes.