Study of the Structural Design Parameters of an Emergency Rescue Station between Continuous Tunnel Portals in a Single-Tube Railway Tunnel Group

In China, emergency rescue stations between continuous tunnel portals have been newly designed and applied in extra-long single-tube mountain railway tunnel groups exceeding 20 km in length. Lower pass rates at emergency exits and slower evacuation speeds on evacuation routes are the major contributors to fire-related fatalities. Therefore, it is very important to use reasonable structural design parameters to ensure the effective evacuation of escapees. This study conducts on-site testing of a railway tunnel evacuation model for 457 people to determine the evacuation speeds. Based on coefficient adjustments, it provides the evacuation speeds of different groups of people in a smoke-filled emergency rescue station. Additionally, a series of simulation evacuation models for 1,500 people in emergency rescue stations between continuous tunnel portals were developed using the buildingEXODUS software. These models simulate the evacuation time under different structural parameters and aim to determine the optimal design parameters by analyzing the relationship between evacuation time and structural factors. The study also investigates the impact of structural design parameters on both evacuation time and evacuation density. The results indicate that, when the width and number of evacuation routes are not optimal, evacuation speed significantly decreases, and more people become stranded in the evacuation paths, which increases the overall risk. This paper recommends that emergency rescue stations between continuous tunnel portals should have at least four evacuation routes, each with a minimum width of 3 m. Additionally, the platform height should be 0.3 m, and the platform width should be 2.5 m.