Evaluation of ventilation flow charts for double-line subway tunnels without air chambers

Abstract

The authors inspect operation of ventilation system in a double-line subway tunnel. It is found that air flow rates required for tunnels and passenger stations differ greatly. For routine operation modes in subway tunnels, the authors evaluate longitudinal ventilation flow chart without station-to-station air chambers, which considerably decreases construction cost of subway ventilation infrastructure. Static pressure fluctuations on outside faces of trains that move in a tunnel in opposite directions are determined. For emergency operation modes of subway tunnel ventilation, under train fire in a tunnel, the authors evaluate a fore-and-aft chart of smoke removal. Toxic emission concentration due to smoke fumes on the way of a breakdown train evacuation is determined. It is proposed to install longitudinal screens in tunnels to ensure safe concentrations of carbon monoxide and carbon dioxide on either way from a breakdown train to a station.