(ffm) On Friday, 21 June, the 72-ton cutting wheel of the tunnel boring machine was let into the starting pit in Europa-Allee from above. The cutting wheel has a diameter of 7.1 metres. 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 Arbeitsgemeinschaft U5 Europaviertel (ARGE) took part in this spectacular event. “A milestone in the project has been reached. The construction of a subway tunnel is not an everyday occurrence and it is great to be present at 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 local residents for their patience and understanding over the past few months.“
A blue 500 tonne truck-mounted crane moves the individual parts of the 580 tonne tunnel boring machine into the starting pit. At a depth of 17 metres, the starting construction is already mounted - the semicircular shield cradle gives the round shield and the cutting wheel stability and brings them into the correct starting position. Gradually, the other components that have already been pre-assembled at the top are lifted down and installed together before the tunnel boring machine starts its journey in late summer. “How much work is involved in this major project and how many specialists do a great job here every day“, VGF Labour Director Wissgott explained.
The tunnel boring machine, which is more than 80 meters long, consists of about 150,000 individual parts, which are assembled by about 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 soil.
The cutting wheel is located at the head of the machine for this purpose. It has a diameter of 7.1 metres and is a custom-made product that is specially adapted to the conditions of the Frankfurt ground. Around 100 peeling knives and 29 cutting rollers work their way through the earth on the cutting wheel. The machine covers a distance of 850 metres per tunnel tube - just over two laps around a sports field. Florian Habersack, commercial director of SBEV, added: „We are pleased to have Herrenknecht, a world market leader on our side, who is a specialist in mechanical tunnel construction.“
The Frankfurt tunnel boring machine bores two tunnel tubes, which will extend the line U5 beyond the main railway station to the west. With a total of four stations - one underground and three above ground - the new and expanding quarter will have an efficient connection to the urban transport network. The lowest point of the future tunnels is 22 meters below the surface.