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Burgholz Tunnel

The Burgholz Tunnel represents a part of the southern detour L 418 of the city of Wuppertal between the Sonnborner Kreuz (BAB 46) and Wuppertal Ronsdorf (BAB 1) and serves to relieve the inner-urban Talstraße (B 7). The route alignment runs within the "Staatsforst Burgholz" recreation area. The Burgholz Tunnel consists of 2 parallel running tubes each with 2 lanes and a hard shoulder. Two emergency footpaths at the sides round off the clear width of 11.0 m. The clear height of the carriageway zone amounts to 4.50 m. The gradient rises by 1.0 % over a length of 783 m and then by roughly 6 %. The carriageways are produced with a transverse gradient of 2.5 % at the inner side of the curve. The portal zones were partially constructed by cut-and-cover and partially by mining means. The mined section of the Burgholz Tunnel was undertaken in tectonically stressed rock with fault zones and partly extremely weathered right up to deconsolidated rock conditions. Underground water was encountered depending on the degree of fracturing and the opening width of the fissures. The amount of water greatly depended on the time of year and the quantity of precipitation especially in the sections driven close to the surface. Overburden heights extended to a maximum of 46 m. The overburden under side valleys was reduced in places to 3.5 m. The northern and southern tubes were driven on the rise. The overall cross-section was excavated in 3 parts in the form of crown, bench and floor. The length of advance at crown level varied according to the rock conditions from 1.00 m in extremely weathered rock to 2.00 m given unweathered ground. The rock was removed by drill+blast over lengthy sections. In fault zones and weathered rock, tunnel excavators were employed. On account of neighbouring residential areas and special structures gentle blasting methods were applied. Following excavation the rock was secured by means of shotcrete, reinforced concrete matting, support arches and a radial anchorage system. Lances were used for the advance supporting of the roof area and rock bolts secured the face. Sections with only shallow overburden were driven protected by pipe umbrellas. Systematic continuous injecting of suspension improved the surrounding rock. Thanks to the application of the various forms of support it was possible to ensure that the tunnel was secured in a targeted and effective manner at any time in keeping with the rock conditions that were encountered. It was necessary to place a shotcrete base invert in particular sections. An umbrella shield was mainly applied for waterproofing purposes although a continuous seal was also used in sections. The underground water is removed via slotted drainage lines with a smooth interior to the foot of the walls. The permanent lining was executed both in the form of an open as well as a closed vault profile with shell thicknesses of between 35 and 50 cm. The sites own concrete mixing plant produced the vault concrete in strengths B 25-WU and B 35-WU. Four accessible and 2 drivable cross-passages link the 2 tunnel tubes. The cross-passages represented the most important part of the logistics for dealing with the site traffic. For fire protection reasons, all cross-passages were provided with fire-resistant bulkheads after the permanent lining was installed. The complicated reinforcing and shuttering work on the 4 portal collars began in October 2004 and was completed at the end of November the same year.

 

  • Country: Germany
  • Region: North Rhine Westphalia
  • Tunnel utilization: Traffic
  • Type of utilization: Road tunnel
  • Client: Regional Office for Roads, NRW, Essen Branch
  • Consulting Engineer: IMM-Prof. Dr.-lng. B. MaidI- Dipl.-lng. R. MaidI, Schüßler Plan, Ingenieurbüro Wendt
  • Construction monitoring: Regional Office for Roads, NRW, Special Construction Group Wuppertal, IMM-Prof.Dr.-lng.B.Maidl- Dipl.-lng. R. Maidl
  • Contractor: Baresel AG, G. Hinteregger & Söhne Baugesellschaft m. b. H.
  • Main construction method: Trenchless
  • Type of excavation: Drill-and-blast
  • Lining: Concrete formwork
  • No. of tubes: 2
  • Tunnel total length: southern tube: 1,886 m; northern tube: 1,787 m
  • Cross-section: 99 m² (standard cross-section), 120 m² (standard cross-section with base invert)
  • Contract Volume: approx. € 82 million net
  • Construction start/end: July 2002 to August 2005
  • Opening: probably 2005