Abstract: Freezing damage causes tunnel structure diseases in cold regions, which are not conducive to tunnel traffic safety. To prevent and control frost damage in Guanshan tunnel, a new type of sideblow air curtain insulation system for coldregion tunnels is proposed. First, the control equation for air curtain barrier efficiency is established, and the main design parameters of the system are optimized. Next, an experimental system of airflow and temperature fields in the thermal insulation device under the action of the air curtain is designed and developed, and the variation laws of jet angle, jet wind speed, external wind speed, and barrier efficiency are explored. The experimental results reveal the following: (1) The optimal jet angle of the air curtain is 55°~75°. (2) The barrier efficiency is inversely proportional to the external wind speed and directly proportional to the jet wind speed. (3) The sideblow air curtain insulation system has a good insulation effect and can effectively prevent the occurrence of tunnel freezing injuries.

Key words: coldregion tunnel, sideblow type, air curtain insulation system, control equation, model test