• Project location:  Berlin, Germany
• Client: Berliner Verkehrsbetriebe (BVG)
• Processing time: 2013 – 2016
• Utilization: Subway tunnel, 2 tubes
• Length: 2 x 1,620 m
• Diameter: 6,67 m
• Overlap: 5 - 17 m
• Machine type: TVM (Mixschild)

Areas of responsibility

• Provision of sub-project manager for sign routes

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Project description

The continued construction of the U5 subway line in Berlin-Mitte will close an important gap between the terminus at Alexanderplatz and the Brandenburg Gate. The line runs under the Spree and Museum Island.

The tunnel was built with 2 tubes and a length of 2 x 1,620 m with a Mixshield TVM from the Max-Engels-Forum to the subway station Brandenburger Tor with three further stops and subway stations.

The undercutting of the Spree and the Spree Canal with a minimum overburden of four meters as well as the undercutting of the City Palace, which is currently under construction, should be mentioned as a challenge. Also worth mentioning are the tangential castle bridge foundation on the Spree Canal and the underpass "Unter den Linden" of the subway line U6 and north-south S-Bahn lines currently in operation.

The typical subsoil conditions in Berlin, consisting primarily of tightly graded, well-drained and therefore free-flowing sand in combination with a very high groundwater table, present a major challenge for the planning and execution of the excavation pit as well as the approach and entry procedures for shield driving.

The main components of the geology in the tunnel cross-section are valley sands, boulder clay as well as stones and boulders. The excavated material is highly abrasive and largely dense.

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