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Tunnelling underneath Frankfurt Kreuz hub

The route of the Deutsche Bahn AG new Cologne-Rhine/ Main line passes beneath the A 3 and A 5 motorways at the Frankfurter Kreuz hub. The Frankfurter Kreuz is one of Europe's busiest free-ways. Thus a heading method had to be selected, which ensured that the permissible surface settlements were adhered to given tricky geology and extremely thin overcapping (8 to 15 m) without closing down traffic. The subsurface is largely composed of quaternary sands and gravels, which markedly interchange to a pronounced degree. The groundwater level lies roughly 20 m beneath the surface arid in turn up to 6 m above the tunnel base. Taking these conditions into consideration, a circular tunnel cross-section was chosen, which with a height of 13 m and 15 m in width, possesses a very large excavated cross-section of 150 m². It was decided to drive the crown protected by an advance HDBV screen. The bench and base had to be created protected by a HDBV trough as the groundwater could not be lowered over a large area. The actual crown drive was undertaken protected by this screen with a length of advance of 1 m. The face was additionally supported by means of a wedge, HDBV columns and through installing shotcrete. Roughly 60 m behind the face, the bench and base HDBV zones were created from the crown base. After the bench and base HDBV zone was completed, extraction ensued with a 40 cm shotcrete support and 2 layers of structural steel lattice installed. On account of the significance of the construction measure and the safety requirements, a far-reaching measurement programme was installed. It ensured fully automatic continuous monitoring of the surface Settlements (24 h per day) with a total of 70 measuring points. The data were transferred online to the measuring centre and evaluated. Control measurements were undertaken parallel to this in order to supervise the fully automatic measurement system. The theoretically predicted surface settlements amounting to < 50 mm could be adhered to. After completion of the extraction work, the inner shell was installed in 10 m long blocks, using watertight concrete with an air cushion membrane as a gliding layer between the outer and inner shells.

 

  • Country: Germany
  • Region: Hessen
  • Tunnel utilization: Traffic
  • Type of utilization: Main-line rail
  • Client: Deutsche Bahn AG and DB Projekt GmbH Köln-Rhein/Main
  • Consulting Engineer: Emch + Berger, Ed. Züblin AG
  • Contractor: Ed. Züblin AG, Walter Bau AG, Heilit + Woerner Bau AG, Bunte
  • Main construction method: Trenchless
  • Type of excavation: Roadheader
  • Lining: Concrete formwork
  • No. of tubes: 1
  • Tunnel total length: mining means 284 m
  • Cross-section: mining means 150 m²
  • Contract Volume: 220 mill. DM
  • Construction start/end: 1996 till 1999
  • Opening: 1999