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Specialized foundation work for a safe flood barrier
Using HVSi foundation piles and grout-injected anchors, Hakkers Funderingstechniek laid the foundation for a safe floodwall in Arcen. For the first phase of the project, the foundation specialist constructed the foundation for the floodwall at the La Tour Meuse apartment complex. In particular, the installation of the grout injection anchors (self-drilling grout anchors) beneath the embankment of the Meuse River required specialized knowledge and a thorough geotechnical analysis.
“The construction design was already complete, courtesy of the Arcen Dike Zone Alliance,” says Arnoud Hoeve, tender manager at Hakkers Funderingstechniek. “The question was: ‘Is this design actually feasible as it was conceived?’ We therefore took a particularly critical look at the implementation and also contributed ideas regarding various details. A good example is the connection between the grout-injection anchors, the tubular piles, and the concrete slab. It’s precisely in details like these that you can achieve significant gains during construction.”
The work in Phase 1 focused on the flood barrier at the La Tour Meuse apartment complex. A 75-meter-long concrete L-shaped wall was installed here, founded on 51 drilled HVSi tubular piles, each 6.5 meters long. During high water, the water exerts a significant horizontal load on this structure. To safely absorb these forces, Hakkers installed 21 grout-injected anchors with a diameter of 400 millimeters at a 40-degree angle. The grout injection anchors were supplied by GeotechMetals, a supplier of anchoring and foundation systems and part of the Hakkers Group. Arnoud: “These anchors, in particular, presented the greatest technical challenge of the project. This is because the grout body is located beneath the sloping embankment of the Meuse River. Whereas the standard design methodology for grout anchors assumes a level ground surface, here we had to account for a steeply sloping subgrade.”
To determine whether the limited soil cover above the grout anchors was sufficient, an additional geotechnical analysis was performed in PLAXIS. This analysis examined the effect of the sloping Maastalud on the stability of the grout body. The calculations showed that, with an anchor angle of 40 degrees, the stability of the soil mass remained assured. Marinus de Heus, commercial technical advisor: “This was a unique situation for us. It’s not often that a grout anchor is installed nearly parallel to the slope of the Meuse riverbank. That’s precisely why it was important to carefully develop the geotechnical justification.”
The successful completion of the first phase has led to a follow-up contract within the same project. This fall, Hakkers Funderingstechniek will install the foundation, consisting of 209 grout-injected anchor piles for the self-closing flood barrier and the glass flood barrier in Arcen Midden. In addition, the company will provide the foundation for the new Watermolen pumping station in Arcen Zuid. According to Marinus, the project clearly demonstrates how important foundation engineering is in an integrated dike reinforcement project. “This project is special to us because of its location and the prominent structure. You won’t see our work once it’s finished, but ultimately, we provide the stability on which the entire structure can rely.”
