Continuation of the mass rapid transit system under the Ruhr river to link Muelheim, Essen and Duisburg in Germany called for a safe and secure method of excavation through very complex and mixed geology of alternate vertical bands of limestone and sandstone with underlying sands and fill materials. The strength of the sandstone and the need to travel under a maximum of 1.85 bar of groundwater pressure most influenced the choice of tunnelling system. A pressurised tunnelling shield method with erection of precast concrete segments behind was chosen. The mixshield had a full face, solid-type cutting head fitted with hard rock disc cutters capable of cutting through the rock whilst still operating as a TBM (tunnel boring machine) using a slurry mucking system. The six precast segments are lifted from the overhead feed by a mechanical erector and bolted together. Grout is injected through the tail seal immediately the next stroke begins and concurrent with excavation. To date an average rate of tunnelling of five metres per day has been achieved in one of the two six metre internal diameter tubes, which include an underground junction and two underground stations. (TRRL)

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  • Corporate Authors:

    Morgan-Grampian (Construction Press) Limited

    Morgan-Grampian House, 30 Calderwood Street
    London SE18 6QH,   England 
  • Authors:
    • Wallis, S
  • Publication Date: 1991-1

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Filing Info

  • Accession Number: 00619948
  • Record Type: Publication
  • Source Agency: Transport Research Laboratory
  • Files: ITRD, TRIS
  • Created Date: Mar 31 1992 12:00AM