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Dortmund Light Railway, Line III, Contract Sections S 10.1 and S 10.2

Contract section 10 represents the final roughwork section passing below the centre of Dortmund from east to west. It is linked up with the Reinoldikirche Junction Station, runs to the Ostentor Station in 2 single-track tubes and then reaches the surface at the Hamburger Straße. A twin-track branching tunnel dips between the 2 route tunnels following a switch zone, crosses the northern route tunnel and arrives at the surface after veering towards the north. The tunnel tubes were mainly produced by mining means. The geological prerequisites were provided by the solid Iimestone marl, which is located beneath an overlying layer consisting of coarse silt, fills and a weathering zone. Given an overburden of roughly 5 m, the marl table was mainly to be found in the roof zone of the running tunnels with the exception of a geological basin, in which the layer boundary dropped to the level of the floor. The drives for contract section 10.1 together with all material transports were handled via a central access shaft with 2 working levels and a cross-passage. The rock was removed using 2 hydraulic tunnel excavators, equipped with a quick-change fixture for shovel, pick or cutterhead so that 2 drives could run parallel to each other. The twin-track branch tunnel was excavated in a western direction from the access shaft once the route tunnels were driven. The outer shells of the tubes were no more than 20 cm apart during the undercutting process. Careful static investigations and reinforcements for the shotcrete shell were essential in order to compensate for the effects of local bedding deprivation. Contract section S 10.2 embraces the production of the ramp and tunnel for the branch off section by cut-and-cover and the follow-up dipping drive by mining means. Towards this end, it was necessary to undercut a residential and an administrative building with a minimum overburden of 1 m. ln order to fulfil the high standards relating to minimising settlements and vibrations, a roadheader with a cutting device was applied. Continuous vibration measurements and permanent settlement checks in the buildings accompanied the drive. The drive on the dip was exacerbated by an unexpectedly high amount of ingressing fissure water. Four wells at each side of the route catered for a reduction in the quantities of water.


  • Country: Germany
  • Region: North Rhine Westphalia
  • Tunnel utilization: Traffic
  • Type of utilization: Underground, urban and rapid transit
  • Client: City of Dortmund, Light Railway Construction Office
  • Consulting Engineer: IMM-Prof. Dr.-Ing. B. Maidl- Dipl.-Ing. R. Maidl, ELE Erdbaulaboratorium Essen
  • Contractor: Wayss & Freytag Ingenieurbau AG, Oevermann GmbH & Co. KG (S 10.1), Wiemer & Trachte AG, Alpine Bau Deutschland AG (S 10.2)
  • Main construction method: Trenchless
  • Type of excavation: Excavator
  • Lining: Shotcrete
  • No. of tubes: 2
  • Tunnel total length: 1,744 m
  • Cross-section: individual tubes 36 to 71 m², Station 185 m²
  • Contract Volume: € 46 million (roughwork)
  • Construction start/end: June 2002 to December 2005