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Vomp-Terfens Tunnel

The Vomp-Terfens Tunnel in the Tyrolean Lower Inn Valley is part of the initial upgraded section for the new Munich-Verona railway axis. The tunnel's eastern part is located to the north of Vomp in "Vomper Berg" rocks. In the east, the tunnel passes through rocks of the Walderjoch anticlinal zone and the "Vomperbach Folds" With closely folded and destroyed rocks mainly Triassic limestone and dolomite, various "Raibler Schichten" layers as well as dolomite formation over a length of 3,400 m. Quaternary glacial sediments are superimposed on these solid rocks. The western part runs over a length of 4,300 m in quaternary soft ground sediments (preterrace sediments, terrace sediments and ground moraines) belonging to the Terfen and Gnadenwald Terraces. In some places, conglomerated delta sediments and further fluvial sediments are present to a lesser degree. The drives are to be executed in soft ground using tunnel excavators and pipe umbrellas or lance umbrellas as advance support, whilst drill+blast is to be employed in solid rock. Waterproofing and the concrete permanent lining follow up supporting with shotcrete. The permanent lining is to be produced in 12.5 m long (mainly reinforced) blocks. The tunnel's waterproofing system is drained and only pressure-tight in certain sections. The rescue tunnel runs parallel to the main tunnel at a distance of 30 m; it was also excavated in advance for exploratory reasons. ln addition, cross-passages between the main and rescue tunnels are set up every 500 m along with 2 rescue shafts with the necessary connecting galleries as well as 3 lateral galleries. At the west portal, 100 m of the main tunnel had to be constructed via cut-and-cover. Altogether, around 1.4 million m³ of material will be excavated and 0.5 million m³ of concrete placed during construction. The technically most sophisticated areas of the tunnelling operations, which are scheduled to last till the end of 2006, relate to the soft ground sections with overburdens of less than 15 m, which have to be driven affected by groundwater. In addition to various advance supporting methods, the groundwater will also be lowered in a number of ways (drainage bores, drilling wells below and above the surface, vacuum wells). Along the soft ground stretch in the direction of Fiecht, the excavation within the Inn's groundwater catchment area will also be executed under compressed air. The work on the permanent lining is scheduled to be finished in 2007.

 

  • Country: Austria
  • Region: Tyrol
  • Tunnel utilization: Traffic
  • Type of utilization: Main-line rail
  • Client: Brenner Eisenbahn GmbH
  • Consulting Engineer: Geoconsult Salzburg ZT GmbH, IMM Prof. Dr.-lng. B. Maidi-Dipl.-lng. R. MaidI
  • Contractor: Strabag AG, Hochtief Construction AG, Ed. Züblin AG
  • Main construction method: Trenchless
  • Type of excavation: Excavator/Drill-and-blast
  • Lining: Concrete formwork?
  • No. of tubes: 1
  • Tunnel total length: 7,735 m
  • Cross-section: 110 to 202 m²
  • Contract Volume: € 175 million
  • Construction start/end: 2003 to 2008
  • Opening: late 2010