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Air Cushion Siphon Wiener Platz, Dresden

As a result of the City of Dresden's decision to revamp the Wiener Platz on the south side of the Central Station, the combined system main collector had to be relocated. The creation of an air cushion culvert was requested in the tender as the most favourable variant and commissioned. The major feature of an air cushion culvert is that the pipe is partly operated as a partially filled pressure line, whose contents can be adjusted as required to the water amounts to ensure the minimum flow speed needed to transport solid matter. The air in the partly filled pipe, which forms the air cushion, naturally is subjected to overpressure in accordance with the depth of the culvert. The air cushion is restricted in the upper and lower chambers by means of a siphon-shaped pipeline guidance. The Ed. Züblin AG was commissioned to produce the air cushion culvert at the beginning of 1998. The DN 2400 sewage disposal line was to be built by means of the pipe jacking method. Pipe jacking took place under compressed air (0.7 bar over-pressure) using a flushing shield developed by Züblin, thanks to which the cutter chamber which is under compressed air, is partitioned off. The extraction of the earth can be monitored by the crew at normal pressure through a window in the partition. There is a large access port into the cutter room available should obstacles have to be removed. The cutter chamber can also be filled with bentonite in order to minimise settlements during short breaks in tunnelling. In the event of high compressed air consumption, a bentonite membrane can be placed in the shield area by means of nozzles. In order to assure the proper functioning of the air cushion, high demands were placed on the alignment of the pipeline. Permissible deviations from the intended position of a maximum of 2 cm were never exceeded over the entire section.


  • Country: Germany
  • Region: Sachsen
  • Tunnel utilization: Utilities
  • Type of utilization: Sewage
  • Client: Aufbaugesellschaft Prager Straße
  • Consulting Engineer: Arbeitsgemeinschaft IPRO, Ingenieurbüro Heinrich
  • Contractor: Ed. Züblin AG
  • Main construction method: Trenchless
  • Type of excavation: Pipe jacking
  • No. of tubes: 1
  • Tunnel total length: 108 m
  • Cross-section: 2.40 m
  • Radius: 700 m
  • Contract Volume: 10 mill. DM
  • Construction start/end: 10 months
  • Opening: 1998