Llogara Tunnel


Albanian Ministry of Infrastructure and Energy




From October 2020 to April 2021


Feasibility study
Final project idea (preliminary design)
Detailed design


Project objectives

Construction of the Filder tunnel (PFA 1.2) and of the connection tunnel to Obertürkheim and Untertürkheim (PFA 1.6) as part of the Stuttgart 21 project.

Project description

The Filder tunnel is a 9.6 km long section which connects Stuttgart Main Station and the airport. Two single-track tapered cross sections profiles lead from the railway station to the branch-off structures and from there to four single-track tunnel tubes. Two single-track tubes branch off towards Obertürkheim and Untertürkheim (PFA 1.6) and two others towards the Filderebene area. In the lower and upper sections the single-track tunnel is being driven by means of TBM, while the shotcrete construction method is applied for the central section of the tunnel. The tunnel is driven in layers of decalcified and calcified Gypsum Keuper which contain anhydrite and are characterised by high swelling capacity.

Project data

Double-track tapered cross sections profiles: 230 + 224 m, branch-off structures: 43 + 64m, two single-track tubes: 2 x 9.2 km, rectangular cross-section – cut-and-cover method: 135 m, 18 connecting structures + 3 engineering rooms, trough structure: 2 x 108 m

Project specifics

Construction of double-track tapered cross sections profiles using the shotcrete construction method with a cross section of up to 17 m with an overburden of 10 – 40 m; compensation grouting to compensate subsidences above ground; sidewall drifts in the area of the connecting structures; z-shaped connecting structures, tunnel driving in calcified Gypsum Keuper containing anhydrite; tunnel driving under structures and under the city railway line U6 by means of TBM with an overburden of c. 28 m.