Simulation-based risk and resilience assessment scenarios for deep subway stations under fire and personnel fatigue

Deep-buried subway stations are increasingly adopted worldwide, but their long vertical egress paths create compound risks under fire due to environmental hazards (temperature, smoke/visibility, toxicants) and physiological fatigue from sustained stair ascent. This study establishes a unified evacuation framework that integrates a stair fatigue–height velocity model with fire-dependent speed reduction factors to quantify egress performance and derive risk-informed time benchmarks for deep-buried subway stations. A stair-climbing experiment with 200 participants was conducted to quantify fatigue-related speed degradation, and a regression-based model was established to represent evacuation velocity as a function of vertical height. Fire and evacuation scenarios were simulated using PyroSim and Pathfinder to assess the combined impact of fire products (temperature, visibility, toxic gases) and human fatigue on evacuation efficiency. Results indicate that the synergistic effects of fire hazards and physical fatigue extend the total evacuation time to 975.8 s, which exceeds the regulatory standard by 62.6% and is 34.0 s longer than the fire-only condition. The time to reach the station hall exit is 586.8 s, 63.0% beyond the standard limit. Based on these findings, the study recommends adjusting safety benchmarks for deep subway stations to 10 min from platform to station hall and 17 min to the outdoor ground level: 4 min longer than for shallow-buried subway stations. This research contributes a quantitative, simulation-based framework for evaluating evacuation performance under compound crisis conditions. It provides insights for the revision of evacuation standards, the design of resilient underground infrastructure, and the development of decision support tools for emergency response planning.