A Review of Tunnel Fire Evacuation Strategies and State-of-the-Art Research in China

After over 30 years of fast economic development and massive construction of infrastructures, China now owns the largest total length of tunnels in the world. However, many tunnels are overloaded with a large traffic volume and vulnerable to fire accidents in operation. Once a fire occurs in the tunnel, the occupants face a dangerous and confined environment and need to evacuate before reaching untenable conditions. Failure in fire evacuation will cause severe injuries and casualties under high-temperature and toxic fire smoke, and many past fire accidents have taught us lessons. Driven by the need for tunnel fire safety in China, many new researches are conducted related to fire evacuation in tunnel environments including full-scale experiments, and new evacuation strategies are carried out with sophisticated tunnel designs and regulations. Hence, this work aims to review these latest developments and studies in China towards better and safer evacuation in tunnel fires. In specific, the paper summarized the evacuation issues in tunnel fires generally and pointed out the unique issues in China. Aiming these issues, the paper then introduced recent evacuation strategies and evacuation research in China respectively. Typical tunnel fire accidents and full-scale tunnel fire evacuation tests in China were discussed in detail as case studies. Detailed evacuation strategies and the exposed issues were analyzed in those tunnel fire accidents emphatically, while evacuation findings of human behavior such as evacuation choices and trajectories were presented according to several field tunnel fire evacuations conducted by the authors. Finally, we highlight the research advances and challenges of fire evacuation in tunnels, as well as the need and directions for future research.