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Brenner Railway Axis: Main Contract Section H8 Jenbach

The contract section H8, Jenbach is part of the northern access route for the planned Brenner Base Tunnel on the railway artery between Munich and Verona. In the narrow Lower Inn Valley the route in this section crosses the Inn Valley motorway, the station and the Jenbach industrial estate several times. The route partly runs along the bank of the River Inn. As a consequence a mainly underground route alignment in a two-track tunnel was selected. In the east the section links up with the neighbouring one H3-6 underground. Then there is a 3.467 m long tunnel section driven by mining means using a tunnel boring machine (TBM) and a 230 m long rectangular tunnel created by cut-and-cover prior to a 610 m long ramp that provides the link to the Stans interconnecting point in the neighbouring section H3-4. The tunnel was excavated from west to east from a 60 m long starting pit, in which subsequently a part of the rectangular tunnel was built. The starting pit was located directly alongside the Inn Valley A 12 motorway. The shield undertunnelled the motorway directly after starting up at an acute angle with an initial overburden amounting to only a half diameter. A grouting zone was executed to minimise settlements. The drive took place practically only in cohesive gravel and sand soils of the Lower Inn Valley gravel and in the groundwater of the River Inn throughout. A rock formation was penetrated at a slight angle over the final 250 m. A hydro-shield with 13.03 m bored diameter was applied. The tunnel was secured by means of  0.50 m t hick segments. A ring comprises 7 + 1 elements and is 2.00 m wide. After completing the driving operations a 20 cm t hick fire protection in situ concrete shell was installed. Rescue shafts were set up at 500 m gaps, which are linked with the main tunnel via rescue passages. The pipe jacking method with a shield machine (4.80 m diameter) and a fluidsupported face were applied to produce the six rescue passages. An advance sealing zone was produced by the jet grouting method to connect the rescue passages to the main tunnel.



  • Country: Austria
  • Region: Tyrol
  • Tunnel utilization: Traffic
  • Type of utilization: Railway
  • Client: Brenner Eisenbahn GmbH
  • Consulting Engineer: ILF/Geotechnik Hammer
  • Contractor: Strabag AG, Ed. Züblin AG, Hochtief Construction AG
  • Main construction method: Trenchless
  • Type of excavation: Tunnel boring machine (TBM)
  • Lining: Reinforced concrete segments
  • No. of tubes: 1
  • Tunnel total length: 3.467 m (TBM), 840 m (cut-and-cover)
  • Cross-section: 13.03 m (bored diameter), 11.63 m (internal diameter)
  • Contract Volume: approx.151 mill. Euro
  • Construction start/end: 2006 till 2010