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Siegkreisel Tunnel

The Siegkreisel Tunnel was built at Betzdorf in the northernmost point of the Rhineland Palatinate, which is intended to relieve the town of Betzdorf of through traffic at the B 62/L 280 Junction. The south portal is located directly on the fringe of the town so that the constricted space conditions provide only a limited area for setting up the construction site. Far-ranging and complicated excavation and supporting Operations for the pre-cuts at the south and north portals (ground and rock nailing, in some cases on a permanent basis) took place prior to the tunnel driving Operations. Curved supporting walls as well as in some cases, permanently anchored in situ linings with natural rock facing are foreseen to secure the pre-cuts in their final state. The tunnel was driven by mining means from the portal in the prevailing compact clay schist via drill+blast divided into crown and bench. The greatest tunnel cross-section of 175 m² is to be found in the enlargement at the south portal, which narrows to a 3-lane section after some 45 m. After a further 50 m the 3-lane section runs into a 2-lane one. As a densely built-up area is located close to the tunnel portal, special blasting methods were employed during the drive, which - as extensive vibration measurements have confirmed, triggered substantially fewer Vibrations than is customary in the case of conventional blasting methods. The portal was provided with a heavy blasting curtain in order to continue protecting the buildings in the vicinity of the south portal. The excavation is secured with reinforced wet shotcrete. Support arches, rock bolts and lances form further supporting elements. An expandable tunnel formwork carriage enabled the complicated tunnel blocks (curved radius ≥ 100 m for the 86-175 m² cross-sections to be produced in water impermeable concrete. Collecting basins and operational buildings are set up next to the portal blocks created by means of cut-and-cover. Further supporting walls along the L 280 and at the north portal are also partially covered with natural stone.

 

  • Country: Germany
  • Region: Rhineland Palatinate
  • Tunnel utilization: Traffic
  • Type of utilization: Road tunnel
  • Client: Federal Republic of Germany, Land of Rhineland Palatinate
  • Consulting Engineer: Müller+ Hereth, lng.-Büro Jagsch, GEC lnnsbruck
  • Construction monitoring: WBI Prof. Wittke Beratende Ingenieure
  • Contractor: HochtiefConstruction AG, Alpine Bau Deutschland GmbH, H. Kirchner GmbH & Co KG
  • Main construction method: Trenchless
  • Type of excavation: Drill-and-blast
  • Lining: Concrete formwork
  • No. of tubes: 1
  • Tunnel total length: 370 m
  • Cross-section: two-lane 86 m², three-lane 125 m²; enlargement at south portal 125-175 m²
  • Contract Volume: approx. € 10 million
  • Construction start/end: February 2004 to October 2005
  • Opening: 2005