EXCAVATION FOR an underground car park in Munich city centre has now completed, to allow follow on work on the brownfi eld site.
As an initial retention system contractor Bauer Spezialtiefbau built a concrete mixed in place (MIP) wall as well as sheet pile walls. Bauer also built a secant pile wall with 900mm diameter piles as the main retention system. The wall is tied back by three layers of anchors that had to be drilled under hydrostatic pressure with groundwater 4m below the surface.
The groundworks solution, which had to cater for an underground tube tunnel cutting across the western corner of the site, also incorporated the reuse of a Benoto pile wall from the existing foundations of a 1970s motorway next to the site.
With the ground supporting a large mixed-use development of offices, flats and retail, ground workers installed 18, 1200mm diameter foundation piles and 77 Gewi uplift piles. Piles were driven using a BG 25 rotary drilling rig and an RG 18 pile driving rig developed by Bauer Maschinen.
The project is due to complete in summer 2008.