Project

Dredging of the trench for the immersed “Liefkenshoektunnel”.

Location : Belgium, Antwerp
Client : Ministerie van de Vlaamse Gemeenschap
Departement Leefmilieu & Infrastructuur
Contractor : J.V. Dredging International – Baggerwerken Decloedt & Zoon
Period : January 1988 – December 1991
Value : € 44.000.000

Scope of work

Dredging works

General Information

The Liefkenshoektunnel is the third road connection under the river Scheldt near Antwerpen.

Description of the works

Based on its extensive experience in this type of works under difficult conditions, Dredging International had executed the dredging of the trench for the immersed “Liefkenshoektunnel”.

This tunnel has an immersed length of approx. 1200 m and is totally buried in sandy grounds.

All the slopes of this trench needed to be dredged by controlled slope dredging to -24 m and -28 m and this following the instructions of the consultants.
The dredging works had to be executed in the river Scheldt in an area with extremely high sedimentation.
The dredged soil consisted of very compacted fine sand just above a layer of very stiff clay.

Dredging works started mid 1988 and were successfully completed in May 1991.

An additional protection structure with bituminous mattresses was chosen to protect the tunnel against damage by falling or sliding anchors.

The 30 cm thick mattresses measuring 10 x 35 m and weighting 250 tons each were designed and prefabricated by Bitumar (a member of the DEME Group) on a site in the Antwerp left bank harbour .

The transport of the mattresses into the Scheldt was carried out on two pontoons loaded with five pieces each. They were manipulated and placed on the tunnel by the giant derrick NORMA by J.V. Bergingswerken (also a member of the DEME group).

Main Equipment

Bucket dredgers : ADRIATICO, IJZER,
Cutter suction dredger RUBENS
Derrick NORMA