Abstract: Abstract: Based on the Shantou Bay Tunnel Project, several key technical parameters such as fire scale, smoke control and exhaust mode, automatic alarm and fire extinguishing measures in fire control and disaster reduction design were studied by investigating related codes and project cases, and simultaneously carrying out fire experiment and numerical simulation analysis. The results show that when the tunnel is equipped with automatic fire extinguishing system, the fire scale can be designed as 50 MW even if the tunnel allows the passage of trucks and trailers. When the tunnel adopts centralized smoke exhaust mode, the roof temperature of the tunnel is lower than 900 ℃, the smoke spread range is less than 300 m, the temperature influence range is 10 m and the visibility influence range is 5 m on both sides of the fire source, the CO volume fraction is less than the critical danger value of 5×10-4, and the evacuation environment is good. When the tunnel is equipped with two different kinds of fire detectors, the alarm can be completed within 60 s. The underwater long tunnel should be equipped with fire hydrants, fire extinguishers and automatic fire extinguishing systems, and the foam-water spray combined fire extinguishing system should be preferred, and the three fire extinguishing zones should operate at the same time.

Key words: Key words: long submarine tunnel, fire design, fire scale, smoke exhaust mode, fire extinguishing measures