Steinbühl Tunnel and Bossler Tunnel


Joint Venture Albaufstieg (ATA) Porr- Hinteregger – Östu – Swietelsky




2012 - 2017


Final Design

  • Providing the TBM segmental lining
  • Final design for the NATM primary lining

Project Description

The project is a part of the new railway line between Stuttgart and Ulm. It comprises the 8.8 km long Bossler tunnel and the 4.8 km long Steinbühl tunnel. Both tunnels have two single-track railway tubes. The single track tubes are connected with cross passages every 500 m. Between the tunnels there is a bridge which is not part of this contract. The Steinbühl tunnel is built by drill and blast technique (NATM), the Bossler tunnel includes some NATM sections and a TBM section (2 x 2.8 km). Additional geotechnical data gained during early NATM drives showed favourable properties of the rock mass, an extension of the TBM drives is possible, in the best case for more than 90% of the tunnel length.
A major investigation and testing programme follows the early NATM works. Based on these data the principles of the observational method will be applied to the design and construction of further NATM and TBM sections.

Project data

Bossler tunnel: l = 8,806m
Steinbühl tunnel: l = 4,847m
Tunnel diameter: approximately 10m
TBM diameter: 11m


Partly sqeezing ground conditions are assumed, in upper layers there is the potential of karst. The design of TBM extension follows the principles of the observational method. The lining is designed for fire loads verified by a testing programme.


iC provides the final design for the NATM primary lining and TBM segmental lining including all details and intersections.