Unique TBM recycled with success
Publicerad: 15 oktober, 2019
The Rotterdamsebaan road is the largest infrastructure project under construction in the Netherlands. When it is commissioned in July 2020, the 3.5 km Rotterdamsebaan road link will improve traffic for commuters and with the aim of significantly reducing congestion on the Utrechtsebaan and other traffic routes in the area.
To complete the project, a consortium consisting of BAM, Wayss & Freytag and VolkerWessels were contracted for design, preparation and realisation operations.
The consortium will also maintain the road for approximately 15 years after construction.
Known as the Victory Boogie Woogie Tunnel and the largest component of the Rotterdamsebaan project, the scope of this vital section was to build two tubes approximately 1.6 km long using mechanised tunnelling technology. For the operation, the project brought in a Herrenknecht mixshield tunnel boring machine (TBM) that had already displayed its capabilities when it excavated the Sluiskil Tunnel, also in the Netherlands, between 2013 and 2015.
Mixshields are specialised in tunnelling through complex ground conditions, especially in the presence of high water pressure and large diameters.
In order to support an unstable tunnel face, this method uses a liquid medium or suspension, which is kept under a controlled pressure.
When the support pressure corresponds to the surrounding earth and groundwater pressure, the necessary balance has been reached. This stabilises the tunnel face, avoids uncontrolled inflow of soil into the machine and minimises settlement or heave on the surface, creating a decisive advantage when the tunnel alignment runs through busy inner city areas, as in The Hague.
Following professional refurbishment of the TBM at the Herrenknecht plant in Kehl, Germany, the machine again proved its worth when it was reused for the Rotterdamsebaan.
From January to July 2018, the more than 1,600 t and approximately 80 m long TBM excavated the first of two 1.6 km alignments, with an inside diameter of 10.15 m.
Following disassembly, return transport and reassembly, the site crew then quickly excavated the second tube between September 2018 and January 2019. The TBM achieved outstanding advance rates of up to 16.9 m per day.
At the beginning of 2019, the Combinatie Rotterdamsebaan Joint Venture celebrated the final breakthrough. The project-specific machine design had already been adapted for the heterogeneous ground conditions of the Sluiskil Tunnel, including sand, silt and clogging-prone clay.
With an open spoke cutting wheel directly transporting material from the cutting wheel centre, as well as the optimally adapted slurry circuit, more than 3.2 km of new tunnel was created in Holland’s provincial capital in just 12 months, with the deepest point of the tunnel falling 33 m below ground level.
In a reference to Dutch painter Piet Mondrian’s work of art ‘Victory Boogie Woogie’ from which the tunnel takes its name, the cutting wheel was painted in yellow, red and blue. Due to the low abrasiveness of the soil conditions, the colours were still clearly visible even after the
final breakthrough.
This article was featured in the Summer edition of Trenchless International. To view the magazine on your PC, Mac, tablet, or mobile device, click here.
For more information visit the Herrenknecht website.