Providing long term protection against erosion to the LG terminal with non woven geotextiles
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Summary:
France - Dunkirk - LNG terminal
BontexGeo
During the construction of the rock armour of the LNG terminal in Dunkirk, Bontec SNW nonwoven was installed underneath as a filter. The SNW nonwoven provides long term stability as it avoids the wash out of sand particles from underneath/behind the rock armour due to wave action.
The LNG terminal in Dunkirk, established by French Electricity producer EDF, represents a capacity of 13 billion cubic metres of natural gas per year and makes an important contribution to the strengthening of the reliability of supply and the functioning of the natural gas market in northwest Europe.
During this project, Jan De Nul cooperated with Bontexgeo for the installation of a nonwoven filter underneath a layer of rock armour, that will protect the inner port from Erosion. In order to lower the stand-in time of the pontoon during the installation, Bontexgeo produced large panels of 15m wide. This was done by stitching together 5m wide rolls in the finishing department of Bontexgeo.
In By doing this, installation on the water could take place a lot quicker compared to standard 5m wide nonwoven product and a big cost saving was realised.
Bontexgeo supplied 250.000 m² of geotextile for this project. An SNW type of nonwoven was selected, as this product offers, next to excellent hydraulic characteristics, an ideal combination of strength and elongation (high energy index), allowing absorption of possible installation damage.
The nonwoven filter provides the long term stability of the rock armour layer in the long term, as it avoids fine sand particles to be washed away from behind/underneath the rock armour layer. As
such, the stability is maintained as shifts or subsidence are prevented.