Weighing in at 2,000 metric tons, the Herrenknecht AG tunnel boring machine is to commence work on excavating two single-track tunnel tubes through the Filder Plateau extending along the south of the Baden-Württemberg capital of Stuttgart. Each tube is 9,468 meters in length. The Filder Tunnel will link Stuttgart's new central railway station with the Filder Plain and Stuttgart Airport. Excavation of the tunnel is part of the major Stuttgart21 infrastructure project. The use of the tunnel boring machine permits material to be delivered and carried off via the highway away from the city center, thereby providing some relief for Stuttgart and its inhabitants.
A new phase has begun in the construction of Stuttgart's underground railway station as political and business representatives celebrated commencement of construction of the Filder Tunnel on Thursday. At the event, CEO of Deutsche Bahn AG, Dr. Rüdiger Grube, claimed: "Construction of the Filder Tunnel is a technical masterpiece highlighting German engineering all over the world."
The Minister of Finance and Economy in the state of Baden-Württemberg, Dr. Nils Schmid, added: "In Baden-Württemberg, tradition and innovation go hand in hand. The tunnel boring machine is a superlative in terms of steel as well as being a technical masterpiece."
CEO Dr. Ing. E.h. Martin Herrenknecht is proud of the 120-meter tunnel boring machine with a shield diameter of 10.82 meters: "Now we can all show how high-tech tunnel boring technology from Baden-Württemberg can be used precisely and safely to build efficient top infrastructures in Baden-Württemberg, in an absolutely environmentally-friendly fashion. Our employees are proud to be able to demonstrate what our technology is capable of – practically on our very own doorstep."
The tunnel boring machine is a multi-mode machine with the result that it is convertible. In the upper section of the Filder Tunnel, it works in closed mode with a screw conveyor while the lower section involves open mode with belt conveyor discharge. This is attributable to the varying layers of rock: the machine is obliged to penetrate sandstone with marls and clays and nodular marl as well as unleached gypsum keuper. The tunnel boring machine will overcome an altitude of 155 meters and an incline of up to 2.5 percent. The only area of the tunnel where the machine is not used is the central section – the geological transition zone where miners will remove the material from the rock using diggers and loosening blasting procedures.
The use of automatic tunnelling technology enables the delivery of tunnel elements and transportation of excavated material via the highway and away from the city center. This relieves Stuttgart and its inhabitants from most of the transport by truck.
Representatives of the Protestant and Catholic churches blessed the tunnel boring machine and gave it the name of "Suse" standing for an acronym of "Stuttgart-Ulm schneller erreicht" (reaching Stuttgart and Ulm faster). Together with the Stuttgarter Nachrichten newspaper, the Stuttgart21 communication agency initiated a media campaign to find a name for the tunnel boring machine. Tunnel godmother Tülay Schmid, whose husband is the Baden-Württemberg Minister of Finance and Economy, gave the tunnel the name "Tülay-Tunnel" for the duration of the construction phase: "The Filder Tunnel should also aim to link people within our state". As tunnel godmother, Tülay Schmid is the earthly representative of Saint Barbara, the patron saint of miners.
An open day was then held on the site for anyone who was interested in finding out more.