Innovative Sea Wall Construction Put to the Test
Research institute Deltares is conducting a series of tests on a vertical sea wall, designed by the Australian company Armour Group.
For the first time, Deltares will be using its flume facility in Delft, the Netherlands, for a customer outside of the Netherlands.
According to Armour Group, their innovative sea wall construction has a significant smaller footprint compared to an earthen levee and is much cheaper compared to concrete.
The sea wall construction consists of a double row of interlocked composite sheet piles that extend above the ground. The two rows are 4 meters apart and the space between them is filled with sand.
A system of geogrids that is inserted in the sand, holds the two rows together but providing enough flexibility for the construction to absorb the strong wave forces.
Composite sheet piles are specially coated to resist very demanding marine environment. They also provide high strength and stiffness and they are light weight.
Real-scale construction in Delta Flume
The tests at Deltares are aimed to provide Armour Group with the opportunity for a full scale load testing. The wave flume is 9.5 meters deep, allowing to construct a 8.5 meters high vertical wall.
The tests included water levels up to 6.5 m and waves generated up to 2 meters, with significant wave height up to 1.5m.
According to Deltares, the first tests at Delta Flume show that the vertical wall is strong enough to withstand high tides and heavy waves.
Project manager and specialist on coastal structures, Mark Klein Breteler at Deltares is surprised to see that the waves show little impact. “The vertical structure bounces back the waves. Most of the time we see the waves gently lapping against the wall. Only occasionally there comes a wave that really attacks the wall, causing a splash up that overtops it.”
Inventor of the sea wall, CEO John Jarvie at Armour Group mentioned the advantage of the small footprint. “For a conventional earthen levees, you need large volumes of clay and sand. This is costly and such large volumes are not always available. Our construction has a very small footprint and needs only a fraction of the sand volume”.
According to Jarvy this can be any sand, of any texture and can even be polluted.