Metro section B Europa Quarter
|Company||PORR GmbH & Co. KGaA . Structural engineering Branch Düsseldorf|
|Principal||Stadtbahn Europaviertel Projektbaugesellschaft mbH|
|Location||Frankfurt - Germany|
|Type||Tunneling, Specialist civil engineering, Structural engineering|
|Runtime||05.2017 - 08.2022|
Extension of the city rail line U5 Europaviertel in Frankfurt am Main
A new, approximately 2,750m long city railway track for the underground railway line 5 in Frankfurt am Main will connect the Europaviertel development area on site of the former main freight station to the city’s underground railway network. In 2017, SBEV Stadtbahn Europaviertel Projektbaugesellschaft mbH commissioned the consortium U5 Europaviertel of PORR Tunnelbau and Stump-Franki Spezialtiefbau with the construction of an underground, 1,160m long section – including the connection to the existing U5 section, the construction of an emergency exit at the point of connection and the construction of an underground station in the course of the underground section.
Facts about the scope of the order
The new underground rail station “Güterplatz” will be constructed using the cut and cover method. In the area of Europa-Allee, a ramp structure will bring the underground line from the tunnel structures to the surface using closed (hydro-shield tunnelling) and open construction methods.
The building in closed construction comprises the construction of two tunnel tubes with a length of 827m in track 1 and 842m in track 2. Sealing blocks and frost bodies had to be produced at the connecting walls to the existing structure before the end of each shield drive at the Platz der Republik.
The difficult conditions of inner-city tunnelling have posed major challenges for all involved. The executing team from PORR Tunnelbau and Stump-Franki Spezialtiefbau mastered this in perfect teamwork based on years of know-how.
Tunnel construction project with a pioneering spirit
For the very first time, a tunnel was built in Frankfurt am Main using mechanised tunnelling. It is part of the new section of the U5 city rail line to the Europaviertel. In September 2019, the 580-tonne tunnel boring machine, which had been specially adapted to the geological conditions of the project, had begun to work its way through the ground. As it moved forward, it simultaneously installed 8,358 segments for the supporting concrete tubes in the tunnels. At the end of May 2021, "EVA" – short for "Europaviertel anbinden” or “connecting Europaviertel" – reached its final position in the north tube. Mining techniques are being used to finish off the last remaining metres to the existing underground tunnel at Platz der Republik.
Working under compressed air: A case for the PORR tunnelling experts
In the meantime, much of the 72-tonne cutting wheel has been dismantled in the south tube in order to continue with the mining advance using the overpressure method. The best possible employee health and compliance with the strictest occupational safety precautions are required. All persons working under compressed air have undergone occupational health screening. The work runs in 3 shifts of 6 hours each. In addition, about 1.5 hours are needed to lock and unlock the pressure chamber in order to gradually acclimatise and deacclimatise the body to the pressure.
Slurry trench wall work near the start excavation pit© Klaus Helbig
Slurry trench wall work near the start excavation pit. The slurry trench wall gripper excavating the slurry trench wall.© ARGE U5
Photo: Tunnel-boring machine with the cutting blade in turquoise. The tunnel-boring machine is still on the factory grounds and will be taken to the construction site soon.© Klaus Helbig