ABSTRACT
Once completed, the Brenner Base Tunnel (BBT) will constitute the world’s longest railway tunnel. The paper describes the construction of the Italian stretch of the tunnel comprised between the Isarco river and the Italian-Austrian border. The project includes 16km of twin tunnels excavated with two large diameter TBMs; 16km excavated with a smaller TBM and 12km excavated by conventional method. The complex logistics and the challenging underground activities will be presented, with special consideration of the mechanized tunnelling works. The geology is extremely complex with different geological formations such as granite, gneiss and schist, interested by the “Periadriatic Fault”, an extended regional fault crossing the eastern alps. Rock strengths up to 250MPa and extreme abrasiveness, squeezing grounds and aggressive waters pose severe challenges to the TBM advance. Furthermore the configuration and design of the tunnel boring machines for tunnel excavation is explained, including all the special plants and equipment required, as well as the study of the articulated conveyor system, ventilation and railway selected for optimizing the complex logistics of the jobsite in order to achieve the ambitious goal.
