Description
The Stuttgart 21 project (S21) comprises the transformation of the existing main station from an above-ground terminal station to an underground through-station with 8 tracks and the construction of 30 km of tunnels. The tunnels include water pipes for firefighting. Due to the length of the tunnels and the resulting filling times, water mains at distances of more than 1 km from the portals must remain constantly filled with water.
The risk of water freezing in these pipes is assessed by one-dimensional aero-thermal simulations. The modelling considers outside temperature variations of the past 15 years. The analysis of the tunnel network identifies short time and local freezing risks only.