Stuttgart 21 – PFA 1.2 Filder Tunnel

Project objectives

Construction of the Filder Tunnel (PFA 1.2) and the feeder tunnel to Oberand Untertürkheim (PFA 1.6) as part of the Stuttgart 21 project.

Project description

The 9.6 km Filder Tunnel links Stuttgart Main Station to the airport. Two double-track tapering cross-sections branch into four single-track tunnels: two toward PFA 1.6 and two toward the Filder plain/airport. The tunnels are driven by TBM. At the Filder portal, buildings, pylons, and the U6 line are crossed with a 12 to 30 m overburden. The shotcrete method is used in the middle and lower sections due to the swelling gipskeuper. Complex structures like the approach area and rescue access are also built with shotcrete. Compensation grouting mitigates settlements with a 10 to 40 m overburden.

Project data

• Track length: 2 x 9.6 km, tunnel length: 2 x 9.4 km. Single-track tubes with cross-sections RQ 4.05, RQ 4.40, RQ 4.70
• Double-track pipe arch: 2 x 230 m. Pillar tunnel with rescue access: 41 m and 63 m
• Turning cavern, 18 cross-cuts, cut and cover: 2 x 71 m, trough

Services

• Detailed design Filder Tunnel SBW and TBM including cross passages, access tunnels, CGV shafts, and open cut construction
• Preliminary and design planning TBM variant, approach, and branching area. Numerous design optimizations and improvements