The Brenner Base Tunnel - an overview of the status of the project
The Brenner Base Tunnel (BBT) runs for 64 km between Austria and Italy, making it the longest underground railway tunnel in the world. The BBT consists of two single-track tubes, cross passages every 333 m, an exploratory tunnel, and three emergency stops. The planning is underway since 1999, and construction began in 2007. More than half of a total 230 km of tunnel construction including 80% of the exploratory tunnel has already been excavated. Especially in the area of the emergency stops, a variety of underground construction activities is carried out in immediate vicinity, partly in very difficult geological conditions. The complexity of the surrounding conditions, with distances between cavities of a few meters only, intersecting structures, excavation sections up to 300 m², and overburden up to 900 m lead to a significant interaction between the structures. The paper will give a detailed overview over the status of the entire project, will describe selected aspects from the excavation works and will give an outlook on the coming challenges and schedule.