Section 10: Urban Rail Transit Safety and Disaster Prevention

Urban rail transit systems are large-scale infrastructure within cities, directly serving passengers. These facilities involve huge investments, long construction periods, complex environmental factors, and high risks. Once operational, they significantly promote urban development. However, disasters can cause facility damage and immeasurable loss of life and property. Therefore, disaster prevention in urban rail transit systems is crucial and requires careful study and serious attention.

Disasters impacting urban rail can be divided into natural and human-induced. Natural disasters include floods, earthquakes, snowstorms, typhoons, landslides, etc. Human-induced disasters include war, traffic accidents, fires, leaks, chemical explosions, environmental pollution, engineering accidents, etc. These disasters are characterized by limited spatial distribution, potentiality, suddenness, and strong randomness in time and location. Reliable measures must be taken to minimize their impact.

For fire prevention, subway entrances/exits and ventilation pavilions must have the highest fire resistance rating. Passenger areas like platforms, stairs, and evacuation routes must use fire-resistant materials. Fire barriers like firewalls and flat-opening fire doors (manually operable from both sides) must be installed. Each fire zone must have at least two safe exits. Fire hydrants, mechanical ventilation systems (combining smoke and exhaust systems for dual use in disasters), evacuation signs, disaster relief facilities, automatic alarm systems, and monitoring systems must be in place.

For earthquake resistance, all underground and elevated structures must meet seismic design codes. Underground structures like subways, built with reinforced concrete, are natural shelters against air raids, requiring special design and construction considerations. Water disaster prevention involves preventing ground floods from entering stations and damaging underground facilities. Structures must be waterproof, using waterproof membranes and coatings.

Electric trains use DC power with running rails as return paths. Over time, reduced insulation can cause stray currents to leak into ballast beds, stations, tunnels, and other pipelines, damaging them and polluting the underground environment. To prevent this, underground foundation segments' steel reinforcement is welded to form an equipotential body (Faraday cage).

Disaster prevention in urban rail transit, especially in subways, must be thoroughly considered during design. For elevated light rail and ground trams, the focus is on providing valuable evacuation time after sudden accidents.