Winter 2015

You don’t see geosynthetics but they’re everywhere

For as long as he can remember, Professor Adam Bezuijen has been fascinated by the combination of water and soil. ‘It started right back as a child, with my bucket and spade on the beach,’ he laughs. That initial research as a toddler at the seaside led him on to technical studies at Delft and an impressive career in soil mechanics.  

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Although since the early 1990s Adam Bezuijen has been known mainly for research concerning drilled tunnels, he began his career with research on dykes, stone revetments and dredging processes. ‘Commissioned by such bodies as the Department of Waterways and Public Works, I carried out considerable research into geosystems: the application of geosynthetics in hydraulic engineering,’ he says. In 2012, together with TenCate he published the book Geosystems: Design Rules and Applications, a scientific treatise full of formulas and models. According to Adam Bezuijen, one of the most important parts was the table of contents, since ‘No one reads such a volume from A to Z.’

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‘You don’t see geosynthetics but they’re everywhere,’ says Adam Bezuijen. ‘These materials contribute to our protection, particularly where geosystems are used in hydraulic engineering: they separate land and water.’ 
According to Adam Bezuijen, it is obvious that in our country below sea level the use of geosystems to separate land from water will only increase. Considerable use of geosynthetics is also made abroad to protect the land against seawater, river water and rainwater. ‘In the United States, TenCate Geotube® systems are used in great numbers to combat coastal erosion. These are large elongated containers filled with sand, which lie buried in the beach to prevent the beach and a substantial part of its hinterland from vanishing into the sea during a heavy storm. These containers break up the waves.’ geosynthetics adam bezuijen 3

A knowledge institute such as Deltares − where Adam Bezuijen, in addition to his chair in Geotechnics in Ghent still works one day a week as a specialist in soil mechanics – plays an advisory role in the production and use of geosynthetics. ‘TenCate sells not only geosynthetics but the whole geosystem,’ he explains. ‘So they advise their customers on how best to use the containers of geosynthetics. This requires research. For example, we have carried out research for TenCate Geosynthetics to determine how the TenCate Geobag® filled with 400 cubic metres of sand can best be submerged in deep water. What kind of wave causes the bag to shift? How can it be positioned as accurately as possible? What shape does the bag of sand take lying on the bottom? Calculating and puzzling out how all this precisely works are things that I like doing.’ 

Much of the research leads to improvement in the protective material. ‘Geosystems must be able to cope with the enormous pressure of sand and water, and the weak point here was always the seam,’ says Adam Bezuijen. ‘There the material was only at 50% strength. In recent years, TenCate has hugely improved this by making the geosystems completely in the factory and engineering the seams in such a way that they’re just as strong as the rest of the fabric. This makes a tremendous difference, because after all a chain is as strong as the weakest link. In fact, although only the seam has been improved, the strength of the geosystems has now doubled. And this opens up even more opportunities for deploying geosynthetics worldwide for the protection of land and people.’

Blue fabric (Tecawork Blue 65287)