Improving construction of the Liefkenshoek
Location of work/project:
Belgium – Antwerp – Liefkenshoek Railway Tunnel
In the construction of the railway tunnel, Bontec NW 25 was used to guarantee the integrity of the fill material, while still allowing the release of pore water pressure, resulting in a prolonged functioning and as such, quicker and more durable construction work can be done.
The freight-only railway line directly connects the eastern and western docks of the Schelde river and link Bundel Zuid with the Antwerp North marshalling yard. It will run under the water bodies of Kanaal dock, Schelde river and Waasland canal.
BonaxGeo provided 130.000 m² of non-woven Bontec NW 25 as a separation layer between the soil and the fill material at the main entrance and exit of the tunnel complex. The Bontec NW 25 is a thermally bonded nonwoven that is often used as a geotextile separator. It complies with all specifications mentioned in the norm EN 13250 of the CE standard as well as with the more severe specifications mentioned in the Belgian technical requirements PTV 829.
In the middle of the road the Bontec NW 25 is used under a geogrid, which is used as reinforcement. The function of the Bontec NW 25 is to maintain the integrity of the fill material and allow release of pore water pressure through and within the plane of the geotextile. The use of Bontec NW 25 eliminates base /subgrade intermixing. From a construction point of view, the use of geotextile greatly helps in the initial stages of the construction by providing a more stable working platform and allows the subsequent filling operation to be carried out more rapidly.
The geotextile separation layer can therefore reduce maintenance, enable better compaction during the construction stage and the required thickness can be achieved using less aggregate because less aggregate is lost into the poor subgrade.