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Escherbergtunnel

The Escherberg Tunnel is located to the west of Hildesheim in the Hildesheim Forest. Starting from the north it comprises:

  • 105 m cut-and-cover
  • 253 m driven by mining means
  • 561 m cut-and-cover
  • 2,618 m driven by mining means and
  • 150 m cut-and-cover.

The maximum roof overcap amounts to 92 m. The northern section of the tunnel is located in Middle and Lower Shell Lime. In addition, a quaternary-tertiary syncline is penetrated. Further to the south, practically the whole sequence of variegated sandstone is passed through under tricky conditions. The underground water level was in some places at tunnel roof height. The NATM was selected as construction method. The major portion of the tunnel was driven on the rise from north to south. A dipping counter-drive was first undertaken at a later stage. In the northern and the southern sections, tunnelling was executed with two advance wall drives, which formed the abutment for the crown, which followed at a distance of roughly 30 m. The excavation in the normal zone of the tunnel was executed as a crown drive. The reinforced concrete inner shell was placed 30 to 40 cm thick. An external seal made of ECB foil with a drainage mat and non-woven fabric placed underneath secures the tunnel vault against seepage water. Three sections of the tunnel were created by cut-and-cover on account of inadequate overburden and the state of the encountered rock. The tunnel cross-section was divided up into fundament and vault sections for concreting. The individual sections were in each case 11 m long and were produced in a cycle with separate mobile inner and outer formwork. The seal, protective concrete and a filter layer were placed on the vault concrete. Then the excavations were evenly backfilled throughout and the land returned to its original state for forestry use.

 

  • Country: Germany
  • Region: Niedersachsen
  • Tunnel utilization: Traffic
  • Type of utilization: Main-line rail
  • Client: Deutsche Bahn AG
  • Main construction method: Trenchless
  • Type of excavation: Drill-and-blast
  • Lining: In-situ concrete formwork (reinforced)
  • No. of tubes: 1
  • Tunnel total length: 3687 m
  • Cross-section: 120-150 m²
  • Contract Volume: 140 mill. DM
  • Construction start/end: 1984-1988 (44 months)
  • Opening: 1988