TBM river crossing for Gdansk air-sea link Apr 2012
Peter Kenyon, TunnelTalk
- Herrenknecht of Germany is awarded the contract to design and build the 12.56m diameter Mixshield that will excavate a challenging 1.1km twin tube highway tunnel under the Vistula River in Gdansk, Poland.
Breakthrough in Gdansk
- Excavation of both tubes of the Slowacki underwater traffic tunnel in Gdansk - the largest diameter tunnel in Poland - is complete.
- Breakthrough at the end of the second bore was achieved by a 12.56m diameter Herrenknecht Mixshield procured by contractor OHL of Spain. Geological conditions while crossing under the Vistula River at depths of between 9-35m proved changeable, with water pressure of up to 4 bar experienced.
- In some sections of the alignment the Mixshield excavated to within 6m of the river bed. In order to keep the underground structure as stable as possible and protect against buoyancy, the thickness of the concrete lining segments was specified as 600mm, each one weighing 18 metric tonne.
- For production of the segments, Herrenknecht Formwork supplied four sets of moulds with an i.d. of 11m, a vacuum lifter and turning table for safe and easy handling of the heavy segments. The company also supplied a separation plant and a guidance system for TBM navigation.
Mixshield completes Gdansk river drives 15 July 2014
Herrenknecht News Release
- Herrenknecht Formwork is awarded the contract for the design, manufacture and supply of the moulds for what are claimed to be the world's largest concrete segments. Each segment, with a thickness of 600mm, will weigh 18 tonne.
- The drive is the final part of the four-phase Slowackiego (Slovacki) Highway Project that, when complete, will link Gdansk airport and the major road routes towards Warsaw in the west and its deep seaport on the eastern side of the Vistula River (Fig 1). Gdansk has the deepest seaport in the Baltic, and is a major cargo hub for Eastern Europe.
- A Spanish-Polish JV of Obrascon Huarte Lain (OHL) and the PBG Group of companies is awarded the €221 million contract to build the final 2.4km section of dual carriageway that makes up the 10.7km route.
1.4km twin traffic tunnel will link Gdansk seaport and airport
- At the heart of the alignment is the twin tube 1.4km tunnel, 1.1km of which will be bored by TBM (Fig 2). OHL has confirmed this will be the largest diameter TBM it has ever operated.
- The project is being carried out on behalf of the City of Gdansk.
- At an internal diameter of 11m, the twin tubes with a two-lane roadway and an emergency pedestrian verge in each, are designed for a speed limit of 120km/h. The tubes will be connected by seven 12m2 cross passages, each 20m in length.
- The drive will run between 9m-35m below the bottom of the river and is expected to be extremely challenging. Geotechnical surveys carried out in 2010 reveal the contractor can expect to traverse ground conditions mainly of sandy soil and gravel types 4b, 4c, and 5 and potentially under the full hydrostatic head of river above (Fig 3).
Fig 3. Tough ground conditions under the Vistula are expected
- Keller of the UK is awarded a €36 million contract to construct the diaphragm walls along the access ramps and around the TBM launch chambers and will apply jet grouting, using its super jet monitors, to enable large diameter soilcrete columns to be installed at considerable depth.
- The ramps on the eastern and western sides of the tunnel will be 40m wide and 340m and 750m long respectively.
- Last year, Polish construction company PBG, which has a 45% share in the Gdansk Slovacki crossing project, carried out another 1.3km underwater crossing of the Vistula in Warsaw, using a 5.35m Herrenknecht Mixshield. The drive formed the final part of new wastewater treatment system for the Polish capital city.
- Gdansk accepts TBM for vital river crossing - TunnelTalk, October 2012
Warsaw microtunnels manage Vistula cleanup - TunnelTalk, April 2011
Add your comment
- Thank you for taking the time to share your thoughts and comments. You share in the wider tunnelling community, so please keep your comments smart and civil. Don't attack other readers personally, and keep your language professional.