The brenner base tunnel

Geological and hydrogeological conditions significantly affect the decision as to whe- ther and where a tunnel is to be built. To determine the appropriate route for the Brenner Base Tunnel, over 35,000 meters of boreholes were drilled at various points over the project area, some of these down to tunnel level. Rock samples were also taken and ana- lysed in the laboratory. Despite the use of modern technology, it is not possible to accurately predict the geo- logical conditions inside a mountain. Therefore, an uninterrupted exploratory tunnel is being excavated as part of the Brenner Base Tunnel project to obtain more detailed in- formation on the nature of the rock along the route. In this way, the excavation can be optimised from both a technical and an economical point of view. On its route from Innsbruck to Fortezza, the Brenner Base Tunnel crosses roughly four different rock types: quartz phyllite, schist, gneiss and granite The geological conditions inside a mountain cannot be precisely predicted even using the latest technology. However, forecasts made by expert geo- logists, prospection drilling and the continuous exploratory tunnel minimi- se the construction risk. 29 BRENNER BASE TUNNEL km FORTEZZA FRANZENSFESTE Venntal Val di Pfitsch Pfitschtal Spina del lupo Wolfendorn Bündner schists Austroalpine Crystalline Complex Brixner granite Tonalit Periadriatic fault zone Central gneiss Brenner Base Tunnel Brenner Base Tunnel AUSTRIA ITALY Val di Senges Sengestal Val di Mules Maulser Tal 30.0 35.0 40.0 45.0 50.0 55.0