The construction of tunnels using conventional construction methods has always been a challenge to every engineer. Here, the engineer’s most important task is the evaluation of the geology and the selection of the right means of securing the excavation face until final completion of the inner lining. Wayss & Freytag already rose to this challenge in 1905 when building a railway tunnel using the conventional tunnelling method in Wasserburg/Inn in gompholite (Nagelfluh) and gravel.
The range of conventional tunnelling reaches from soft rock tunnelling (e. g. a metro tunnel in Munich gravel) and tunnelling in compressed air (e. g. Ostbahnhof metro station in Munich in Tertiary formations below groundwater) to classic drill and blast drives (e. g. Rennsteig Tunnel on the A 71 motorway, which, with a length of 8 km, is the longest motorway tunnel in Germany).
The Henndorf bypass lead to a noticeable relief of traffic congestion. Centrepiece of the bypass is the double lane 2,150 meters long road tunnel, which is now used by approx. 20,000 vehicles per day.
The Roppen tunnel between Innsbruck and Landeck in Austria was made safer by the construction of the second tube. The 5,069 meter long tunnel was driven conventionally.
6 km railway tunnel from Stuttgart central railway station to Bad Cannstatt as part of the large-scale project „Stuttgart 21“.
The extension of the Klaus tunnel string with the 2nd tubes on the A9 Pyhrn motorway in Austria means the end of oncoming traffic and thus provides better safety for 18,000 drivers per day.