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Tunnel Eichheide

The Eichheide Tunnel is one of the 11 tunnels on Lot B of the Deutsche Bahn AG's new Cologne-Rhine/Main line. It lies between Limburg and Montabaur in the community boundaries of Nomborn and Heilberscheid. The tunnel starts in the Eisenbachtal valley (north portal), passes through the Eichheide area with a maximum overburden of 70 m, crosses below the Nentershausen-Heilberscheid district road and reaches the surface again in Wiesengrund (south portal). The route proscribes an arc with a 4,100 m radius. The maximum gradient amounts to 29 ‰. The total length amounts to 1,750 m with roughly 1,710 m driven by mining means. From the Eichheide Tunnel, an approx. 90 m long access tunnel leads to a shaft with an elevator. The shaft is 60 m deep and is 8 m in diameter. Devonian solid rock was encountered beneath a thin layer of slope debris and loam which belongs to the Laubach layers in stratigraphic terms it comprises silver to dark grey clay schists, interstratified with fine Sandstones and sandstone banks of varying thickness. In the central area of the tunnel, a tertiary basalt funnel is encountered so that in the peripheral zone mechanically destroyed rocks, fault systems and major ingresses of water are expected. From the pre-cut North in the Eisenbachtal, the 147 to 164 m² tunnel cross-section is excavated partly by mechanised means with tunnel excavators but mainly using blasting with subsequent securing with shotcrete. The crown construction method was chosen with a gap of roughly 300 m followed by the bench and base. ln this connection, the length of advance varies in the crown depending on the geology between 0.80 and 2.40 m. ln order to secure the ground, a 15 to 35 cm thick, reinforced shotcrete shell is foreseen after each round in accordance with the construction planning approved by the responsible test engineer (Prof. B. Maidl, Bochum). The bolting system installed radially in the following phase provides a shear connection for the surrounding ground. As the groundwater level is located at up to 60 m above the tunnel roof, the structure has to be completely sealed with welded plastic membranes once the tunnelling operations are over. Thereafter, the inner shell of watertight reinforced concrete will be installed in blocks of 12.50 m. The base invert is between 50 and 70 cm thick, the roof vault between 35 and 55 cm.

 

  • Country: Germany
  • Region: Hessen
  • Tunnel utilization: Traffic
  • Type of utilization: Main-line rail
  • Client: Deutsche Bahn AG and DB Projekt GmbH Köln-Rhein/Main
  • Main construction method: Trenchless
  • Type of excavation: Drill-and-blast
  • Lining: concrete formwork
  • No. of tubes: 1
  • Tunnel total length: 1750 m
  • Cut-and-cover: 37,5 m
  • Cross-section: 147 m² to 164 m²
  • Contract Volume: 68,5 mill. DM
  • Construction start/end: 1998 till 2000
  • Opening: 2002