Construction phase 2
The U55 Shuttle Line from Hauptbahnhof to the Brandenburg Gate
After the urban rail (S-Bahn) passageway is demolished, subterraneous curtains and drill foundation piles are installed. They form the exterior walls of the excavation pit, i.e. the outer shell of the structure. They must be able to withstand pressure from the groundwater.
In order to reduce delays in the construction work as well as impact on surrounding buildings, the subterraneous curtains are set up by curtain grippers. To make sure they are completely impermeable, metal jointing is also installed between the individual panels. A floor is then injected into the soil under high-pressure conditions (HPI) to a depth of 20 metres, in order to seal the excavation pit against groundwater from below as well.
Construction phase 2: Subterraneous curtains
Action: Constructing the subterraneous curtains
Site surface area:
Area 1: (west of Wilhelmstraße) approx. 2200 sqm. Fencing surrounds the construction site throughout this period, and is used for art displays.
Area 2: (east of Wilhelmstraße) approx. 1800 sqm. The subterraneous curtains serve to hold back the groundwater, and must be cast in a single piece. In isolated cases, obstructions may require night work.
Emissions:
High noise pollution: "open construction site"
Material transport:
Removal of excavated earth Delivery of cement
Site traffic :
approx. 2-3 lorries per hour