Construction phase 3
The U55 from Hauptbahnhof to the Brandenburg Gate
The initial pit for the tunnelling work corresponds roughly to the future entry structure (approx. 28 x 25 m) of the metro station. Due to the high groundwater level, as well as the prohibition on lowering it, the pit is sealed on all sides and secured in the soil with anchors.
The shaft can be finished in approximately 10 weeks. A cover over the future structure will first be built on the subterraneous curtains. Excavation will then be performed under this cover.
The main advantage of this method is that it minimizes inconvenience for local residents by enabling most of the construction work to take place under the cover.
Construction phase 3
Action:
Temporary cover, soil excavation
Emissions:
Building the cover: moderate noise pollution. Construction work will then be done underground.
Excavation:
Low noise pollution during excavation. Moderate noise pollution from loading and traffic. Dust pollution is reduced by sprinkling.
Material transport:
Removal of excavated earth, delivery of concrete.
Site traffic:
2-3 lorries per hour