Fast foundation on 'thick water' with EPS and reinforced soil

On behalf of the Department of Public Works, VeenIX is widening the A9 between the Badhoevedorp and Holendrecht interchanges. The A9 is located in quite a swampy and complex environment. In order not to lose too much time with pre-loading and to save space, EPS and reinforced soil constructions are frequently used. A monster job for Bonneveld Gewapende Grondconstructies BV, which is taking care of the execution. 

In 25 years, Bonneveld in its present form has grown into a specialist contractor. The reinforced soil construction department has seen strong development and has been building structures throughout the country for over a decade. Bonneveld is part of Joosten Concepts, a partnership between various suppliers, manufacturers, engineers and contractors. "As such, we take care of all EPS and reinforced soil constructions here on the A9," says Leon van der Heiden, work planner at Bonneveld. Joosten Concepts works according to the OLA principle: design, supply and install. "So we are responsible for the latter and also bring in a bit of knowledge. Moreover, with the contracting company behind us, we can pick up work very broadly. And that is appreciated."

Ideal foundation

In those places where space is limited and where slopes cannot be installed, reinforced soil offers a solution. "Just as concrete is reinforced with steel, we reinforce soil with plastics. Thanks to this technique, you create a structure of soil that can also absorb tensile forces, which makes it an ideal foundation for (rail) roads," Van der Heiden explains. "In turn, EPS lends itself perfectly to effective and fast foundations on 'thick water'. Together with Joosten Concepts, we offer a total package to clients, from scratch to the right solution with the desired facing tailored to each project."

Electric cutting sword 

Bonneveld is now working on the fifth subproject within the scope. "Near the Schiphol Bridge, we installed the EPS structures in four phases, totaling some 31,000 m3 of EPS," says Hans van Beek, Bonneveld's contractor. Half of the Netherlands has driven by, in the bowl of the exit ramp at the Schiphol Bridge all the Styrofoam was in storage. The EPS is used to minimize the non-load bearing subsoil. The EPS blocks are fitted under the abutments around the foundation piles using a self-developed electric cutting blade. This ensures a more accurate result without creating unnecessary waste." EPS structures, once installed, must be protected from outside influences. "On this project, two variants were applied: foil and concrete canvas. Concrete canvas are concrete mats that are rolled out and after adding water they harden."

Various anchors and structures

In addition, Bonneveld installed nearly 500 meters of sheet pile anchorage with geosynthetics secured in the soil body. "It is a faster method and also takes up less space compared to traditional grout anchors," Van Beek knows. "The sheet pile anchorage can be easily dismantled without leaving any materials behind and is also cheaper." For a temporary bridge over an on- and off-ramp of the A9 motorway, Bonneveld further created two reinforced soil structures to lay the bridge on and allow the on- and off-ramps to run over it. In addition, two structures are being put in place for a bypass that is yet to be constructed, with a section also being put in place directly for the final situation. The final situation will be constructed with a maximum 65° slope so that a green look can be created here later. In total, about 500 meters of reinforced soil have been installed, with a maximum height of 6 meters.

Over the past decade, Bonneveld has realized several pile mattresses and Terre-Armee walls in addition to hundreds of reinforced soil structures and EPS structures. A specialist for good reason, then.