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Klingenberg Dam Renovation Auxiliary Water/Flood Relief Tunnel

After practically 100 years of service the Klingenberg Dam structures and facilities in the eastern Ore Mountains are desperately in need of renovation. It is thus intended to upgrade the flood relief installation through constructing a flood relief tunnel (HWE tunnel). A number of alternatives were examined before coming up with the mode of operation and tunnel lining. The most favourable one was a pressure tunnel with in situ concrete lining. The roughly 3,310 m long tunnel serves to divert flood water of up to 30 m³/s and also to transfer untreated water from the Klingenberg Foredam and the Rauschenbach Dam. After examining all the possibilities, it was decided to choose a mechanised drive to produce the tunnel. The HWE tunnel is thus being driven by a hard rock tunnel boring machine with a 3.90 m external diameter. The tunnel is to be lined with a 25 cm thick in situ shell. The DN 500 pipeline will be concreted into the base zone for transferring untreated water. High demands are placed on the permanent lining as a result of the high external water pressure of up to 8.2 bar as well as the high internal water pressure of 3.6 bar. ln regional geographical terms, the HWE tunnel runs in the anticlinal zone of the Fichtel and Ore Mountains, which constitutes metamorphic, Precambrian ranging to old Palaeozoic series of rocks, mainly gneisses. In particular, it penetrates the Freiberg gneiss dome comprising slate grey gneiss. The tunnel's route alignment was established on the basis of geophysical investigations. In this way, the fault systems that are close to the valley can be avoided. The groundwater table in fissured rock is located at a maximum of 82 m above the tunnel route. On account of the limited space available at the point selected for the planned tunnel portal, a large number of alternatives for setting up the site installations were investigated during the course of the plan approval procedure. High demands are also placed on site operations on account of the tunnel's proximity to a drinking water protection zone.


  • Country: Germany
  • Region: Saxony
  • Tunnel utilization: Utilities
  • Type of utilization: Flood Relief Tunnel
  • Client: Landestalsperrenverwaltung Sachsen
  • Consulting Engineer: Spiekermann GmbH
  • Main construction method: Trenchless
  • Type of excavation: Tunnel boring machine (TBM)
  • Lining: Concrete formwork
  • No. of tubes: 1
  • Tunnel total length: 3,310 m
  • Cross-section: diameter: inner: 3.10 m, outer: 3.90 m
  • Contract Volume: approx. € 15 million
  • Construction start/end: 2005 to 2007
  • Opening: 2007