(ffm) On Friday, June 21, the 72-ton cutting wheel of the tunnel boring machine was lowered from above into the launch pit in Europa-Allee. The cutting wheel has a diameter of 7.1 meters. The managing directors of Verkehrsgesellschaft Frankfurt (VGF), Michael Rüffer and Thomas Wissgott, the managing directors of Stadtbahn Europaviertel Projektbaugesellschaft (SBEV), Ingo Kühn and Florian Habersack, as well as representatives of the U5 Europaviertel working group (ARGE) attended this spectacular event. "A milestone in the project has been reached. The construction of a subway tunnel is not something that happens every day and it is great to be part of this event," VGF Managing Director Rüffer was pleased to say. Kühn, Managing Director of SBEV, was also impressed: "This is already a special moment, which required a lot of effort from everyone beforehand. We would therefore like to thank all those involved as well as the residents for their patience and understanding over the past few months."
A blue, 500-ton truck-mounted crane moves the individual parts of the tunnel boring machine, which weighs a total of 580 tons, into the launch pit. At a depth of 17 metres, the start-up structure has already been assembled - the semi-circular shield cradle provides stability for the round shield and cutting wheel and brings them into the correct starting position. Gradually, the other components already pre-assembled at the top will be lifted down and assembled together there before the tunnel boring machine starts its journey in late summer. "How much work goes into this major project and how many specialists do a great job here every day is something we can illustrate on such dates," explained VGF Director of Labor Wissgott.
In total, the tunnel boring machine, which is over 80 meters long, consists of around 150,000 individual parts, which are assembled by around six to ten people per shift. With the power of about two Formula One racing cars (1305 hp), it will work its way through the Frankfurt ground.
The cutting wheel is located at the head of the machine for this purpose. It has a diameter of 7.1 meters and is a special design that has been specially adapted to the conditions of Frankfurt's soil. Around 100 peeling blades and 29 cutting rollers work their way through the earth on the cutting wheel. The machine covers a distance of 850 meters per tunnel tube - a little more than two laps around a sports field. Florian Habersack, commercial director of SBEV, added: "We are pleased to have Herrenknecht, a world market leader who is a specialist in mechanized tunnel construction, at our side."
The Frankfurt tunnel boring machine is drilling two tunnel tubes that will extend the route of the U5 line westwards beyond the main station. The total of four stations - one underground and three above ground - will provide the new and expanding neighborhood with an efficient connection to the city's public transportation network. The deepest point of the future tunnels is 22 meters below the surface.
