From Hildburg Bruns
Operation Tunnel Uplift. The subsoil under the subway line 2 at Alexanderplatz is to be stabilized with 56 cement shots. The intervention begins in March and costs around 10 million euros.
Passengers from Pankow in particular hope that the tunnel surgery will work. After the summer holidays, the U2 should roll back to double-track normal operation. Now there is shuttle traffic between Senefelderplatz and Klosterstraße – in the worst case only every 15 minutes.
From the excavation pit on the left, lances are drilled under the subway tunnel. A cement liquid that stabilizes the subsoil flows out of the tubes every 50 centimetres Photo: SenUVK
The cause is under Alexanderplatz: the subway tunnel runs close to the construction pit for a high-rise building at a distance of only 0.80 to 2.50 meters. The excavation wall (one meter thick) got a dent, the floor slid, the subway tunnel moved.
The result is now 3.8 centimeters long subsidence damage, cracks. To be on the safe side, a track was shut down in October, as was work on the skyscraper.
How is the repair going now? From the excavation pit, 56 lances (each 6.5 cm in diameter) are drilled into the ground under the tunnel. In these tubes there are holes every 50 cm through which a cement liquid is pumped into the ground. A cement cushion is to be created under the tunnel and the damaged track is ultimately to be pushed back into its original position.
Covivio Managing Director Daniel Frey (centre) with project manager Andreas Tichay (left) and BVG board member Rolf Erfurt Photo: Ralf Gunther
“It’s a huge crap when the artery stops working,” says Daniel Frey (50), the skyscraper’s builder. The head of the Covio company also says: “I know it takes far too long, but we can’t afford to mess it up.” Luckily for the BVG, she had concluded a neighborhood agreement with the investor, which regulates such damage.
For Mitte’s city councilor Ephraim Gothe (59, SPD), the incident is not a rejection of further skyscraper projects on Alex: “The building site is difficult everywhere along the Spreetal. We don’t have a granite block underground like in Manhattan.”
The excavation for the planned skyscraper by builder Covivio. From here the cement shots are drilled under the subway tunnel Photo: Siegfried Purschke
To make the U2 chaos at least a little more bearable for passengers, the M1 tram line between Pankow and mid-April should run every 7.5 minutes instead of every 5 minutes.
The high-rise project next to the Hotel Park Inn will be delayed by ten months as a result of the accident. The 134 meter high building with offices as well as apartments and shops in the base will not be complete until the end of 2026.