In the past Wayss & Freytag was significantly involved in the development of mechanized tunnelling techniques. For example, they initiated the support of the tunnel face by means of a bentonite suspension and air-cushion. With the so-called “slurry shield” this technique was brought to operational maturity. Wayss & Freytag is a pioneer of this technique and has in the meantime driven more than 150 km of tunnel using slurry shields. In addition, more than 80 km of tunnel were driven using earth pressure balance shields and 30 km using hard rock TBMs.
Greatly varying geology required different driving methods during the construction of the Uetliberg Tunnel in Switzerland. The 4.4 km long road tunnel connects the Birmensdorf bypass with the existing national road Zurich-Chur.
Tunnel for a gas pipeline under Scruwaddacon Bay, Ireland was awarded the prize for best environmental initiative 2015 during the Tunnelling Awards at the International Tunelling Association.
Simultaneous drive of two tunnel tubes with two EPB shields for the high-speed Channel Tunnel Rail Link.
Four-track extension of the Olten–Aarau railway line, Switzerland: the 2.6 km long Eppenberg tunnel helps to eliminate the traffic bottleneck.