Study of the pressure loads on cavities in high-speed railway tunnels

The tunnel passage of a high-speed train leads to pressure waves inside the tunnel, which can affect the installations inside of the tunnel, as well as the structures of the train and the tunnel in a negative way and may lead to discomfort of the passengers. Modern twin-bore tunnels have small cross-sectional areas, no ballast bed and can be very long, like the recently opened Gotthard-Base-Tunnel. This leads to strong pressure waves, which may steepen over the length of the tunnel. The tubes are interconnected with pressurized crossways, which act as escape way for both tubes. The cross-passage is separated from the tunnel by air-tight doors, whose durability can be decreased due to the loads induced by the pressure waves. At both ends of the cross-cuts, the tunnel's cross-sectional area is enlarged leading to cavities inside the tunnel. Different cavity geometries were studied concerning their influence on the pressure waves. A special attention was paid at the possible decrease of the loads on installations, particularly cross-cut doors, inside of the cavities. A life time assessment was performed for a generic cross passage sliding door. The studies were performed experimentally at the German Aerospace Center Gottingen and numerically at the Austrian Institute of Technology.