Sealing with bentonite mats crucial part Juliana Canal

The widening of the Juliana Canal is being carried out over a total length of some 4 kilometers between Berg aan de Maas and Sluis Born. Approximately half a million square meters of bentonite mats will provide a water-inhibiting layer at the bottom of the canal. This makes it one of the most crucial parts. "Before the first meter was laid, the system was extensively tested," says Rijk Gerritsen, technical director at Naue Nederland. 

Rijkswaterstaat and Van den Herik-Sliedrecht were faced with a dilemma: how to seal the bottom of the Juliana Canal in a robust, sustainable, safe and executionally efficient manner? "Important consideration in this was the very short time frame available for implementation of approximately 6 to 8 months," said Rijk. "In addition, the Limburg subsurface conditions with a lot of gravel and a cover with hydraulic bricks on the seal require a high robustness of the sealing system. On all these points, the Naue bentonite mats were evaluated positively."

Widening of Juliana Canal with the installation of bentonite mats on the canal bottom and embankments. After installation of the seal, they will be covered by stone layers of various grades.

High quality geo-building materials

The German family business Naue is a specialist in geo-building materials for civil engineering. "Almost forty years ago, Naue invented the bentonite mat and these are still being further developed," says Rijk. "With our high-quality geo-construction materials, hydraulic structures are designed and executed in a smarter way. And we develop high-quality geo-construction materials for a long technical lifespan of 50 to as much as 120 years."

Comprehensive tests

The bentonite mats for the Juliana Canal are about 2 cm thick and of heavy quality. They were extensively tested in advance through field tests. "The challenging conditions of the Juliana Canal were simulated and tested in advance, including the Limburg subsoil with gravel and stones. Tests included a travelling crawler crane and a towing ship anchor over the stone lining. In the process, Naue's bentonite mats came out of all the tests damage-free." 

Huge operation

Each production of bentonite mats undergoes extensive quality testing in the laboratory before the materials are shipped to Limburg. "It is a huge operation, both in production, quality assurance, logistics and installation," said Rijk. "There are eight to 12 trucks a day with bentonite mats going to Limburg, a total of almost 400 trucks." 

Installation

Once on site, the next challenge awaits: applying in the three separate work areas simultaneously. This requires a lot of coordination. Each work section has its own implementation team. The installation of the bentonite mats is therefore done in detailed coordination with the implementing contractors on site, such as Van den Herik as main contractor, but also with subcontractors such as Boskalis, Jac Rijk, FL, Ermers Grondverzet and many others. "This project is a real team effort. That makes me, colleagues and many other partners in the project enormously proud."

Smart solution

According to Rijk, the choice of bentonite mats is an optimal solution for a mega-project such as the widening of the Juliana Canal. "It is robust, watertight and during installation you are not or hardly dependent on weather conditions. The bentonite mats are applied in a large number of square meters per day with a well thought-out execution method and specialized execution teams. This makes it a smart, sustainable and cost-effective solution for hydraulic engineering projects such as the Juliana Canal."