Numerical Modelling and Intervention Measures for Snow Avalanche Protection of the Blattbach Railway Tunnel

Abstract

Snow avalanches represent an undeniable reality in the Swiss Alps both as a geomorphic process and as a type of hazard, causing fatalities, damage to structures and infrastructures. The potential damage of snow avalanches must be seriously taken into consideration when new infrastructure is planned in snow-avalanche prone areas, or to protect existing ones. The Matterhorn Gotthard Bahn railway line is a Swiss infrastructure periodically subjected to snow avalanche hazard in some critical area. This research, in the frame of the practical applications that SUPSI (University of applied sciences of southern Switzerland) promotes within the civil engineering bachelor's degree program, provides a preliminary study aimed at investigating the best protection measure for avalanche risk mitigation of the infrastructure. Snow avalanche simulation are performed and calibrated based on available data obtained from historical events, allowing to estimate the avalanche debris height, length, and speed. On these basis, three solutions are proposed to handle avalanche situations, respectively an increase of the existing tunnel length before and after the critical area, some deviation earth-compacted embankments, or avalanche protection steel barriers. Different solutions are analysed and compared in terms of efficiency and costs.