Wiental Valley Main Sewer

The Vienna Valley Main Sewer describes the tunnel that is being constructed below the Vienna River in the heart of Vienna. Work on this project in downtown Vienna began in Mai 2003. The 2,600 m long tunnel below the Vienna River has an excavated diameter of 8.60 m and is being driven with an earth pressure balance (EPB) Shield Machine. A single-layer segmental lining with double sealing gaskets will be installed. The tunnel is being excavated at a depth of approximately 35.0 m and is entirely located in groundwater (2.5 bar). Eight shafts at depths of up to 40 m are being built along the tunnel route. They are being constructed using the diaphragm wall method (road header diaphragm wall) and with bored pilings, which are 2.0 m in diameter The shafts are to be connected by mining means protected by jet grouting. The Vienna Valley Main Sewer crosses underneath the Vienna Metro in one area, where the overburden is only about 3.0 m. In order to compensate any possible settling, underpinning injections are being carried out here. The tunnel route runs through the Vienna "Tegel", which is made up of tertiary silts, sands and clays. As was predicted, sand inclusions were encountered during the drive. The Vienna Valley Main Sewer is scheduled to be completed in April 2006.

• Country: Austria
• Region: Vienna
• Tunnel utilization: Utilities
• Type of utilization: Sewer
• Client: Vienna City Council
• Consulting Engineer: A. Pauser Engineering Office, University Prof. Harald Ogris
• Contractor: Bilfinger BergerAG, BB Bauges. m.b.H., PorrTechnobau und Umwelt AG
• Main construction method: Trenchless
• Type of excavation: Shield machine (SM)
• Lining: Reinforced concrete segments
• No. of tubes: 1
• Tunnel total length: 2,480 m
• Cross-section: 58.1 m²
• Contract Volume: € 55.18 million
• Construction start/end: 2003 to 2006