View Into Munich’s Deepest Construction Pit

At around 30 metres depth, construction of the new regional train station Marienhof is progressing. Currently, the connecting tunnel between underground station Marienplatz and the new stop of the 2nd regional train main line is under construction. To avoid water infiltrating from the outside, the tunnel is drilled under 0.4 bar pressurised air. The first milestone has been achieved: Drilling of the tunnel type F until the crossing area has been completed – now, the cross-connection (type G) until the existing elevator shafts is being built. Tunnelling is executed around the clock during three shifts.

The design of the tunnel is produced by our joint venture partner ILF – at SSF we designed the pressurised chamber (temporary structure) and the “connecting block” from the station until the drilled tunnel .

At the same time, the first of in total eight sections of the floor slab part 1 at around 43 metres depth is reinforced. At the remaining parts of the floor preparations are ongoing for example the base layer, welding works at the primary supports and placing of the fresh concrete composite film.

Numbers & facts about the floor slab:

• At its deepest point, the lower edge of the floor slab is at around 45 metres underneath the earth
• The floor slab is built in two layers to avoid heavy cracking during concrete setting as well as the associated high heat generation. Overall, the floor slabs part 1 & 2 will be more than 4 cm thick.
• The floor slab part 1 alone requires more than 10,000 m³ of concrete and 2,000 t of reinforcement steel