Abstract: There is a lack of sufficient emergency exits (shelters) for disaster prevention, evacuation and rescue, because it is difficult to construct shafts for underwater railway shield tunnels. To address this challenge, the designs of typical underwater railway shield tunnels is summarized firstly. Then, the evacuation and rescue modes are classified, and the hierarchical standards of under-rail evacuation walkway and emergency exits with vertical shaft are specified, based on the evacuation psychology in confined spaces and staircases. Findings are as follows: (1) Emergency rescue stations should be established for tunnels exceeding 20 km in length to deal with tunnel fires, while vertical evacuation modes should be adopted for tunnels under 20 km to deal with the non-fire accidents. The functional design of under-rail evacuation walkway and the quantity of emergency exits with vertical shaft require graded design based on tunnel length, underwater shield section length, and water section length. (2) It is recommended that the ambient illumination be ≥ 40 Lx, to ensure the safety of longdistance evacuation. In addition, the design methods for the cross-section and length of under-rail evacuation walkway are established for both non passing and passing rescue vehicles. (3) The classified standards for emergency exit with vertical shaft and evacuation auxiliary facilities, including escalators and straight ladders are proposed. Meanwhile, the rest platform is suggested to add every 10 m of height difference, considering evacuation psychology in dark confined spaces and stairwells.

Key words: underwater railway tunnel, evacuation and rescue mode, under-rail evacuation walkway, emergency exit with vertical shaft, hierarchical design