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High 5 Solutions (h5s) specializes in the application and removal of anchor systems. By applying 100% removable sonic screw injection anchors (SSI anchors), h5s is making an important contribution to a circular construction process. BAAK has also embraced the technology. An interview with Peter Bongers of h5s about the added value of sonic drilling technology.
Now five years later, sonic drilling in foundation engineering is proving to be an unmitigated success. "We contribute to many renowned projects at home and abroad," says Bongers. "We moved into new premises in Vianen last year and commissioned a sixth machine. The Cat 352 is heavier than our other machines and especially suitable for the heavy segment of micro piles and grout anchors that we immediately deployed on the Blankenburg connection. With this machine we can also drill anchors under water if required."
"The added value of the sonic technique includes the very limited impact of vibrations on the environment," Bongers continued. "The high accuracy of application and the possibility of faster penetration into very hard soil layers (>20 MPa) also speak in favor of the sonic drilling technique. And all that at lower energy consumption and with fewer adjuvants compared to conventional drilling techniques. With the experience we gained within sonic techniques, we developed numerous new possibilities. Think of disciplines such as the installation of numerous anchoring structures, the installation of micro-pile structures, destructive drilling, recovering obstacles from the soil or the installation of injection hoses for soil sealing projects." These developments earned h5s a number of patents, both in the Netherlands and for much of Europe.
"What you put in the ground, out of respect for nature and the environment, you should also be able to remove it again," Bongers believes. "One of our patents relates to the sonication of anchoring elements and the complete removal of the screw injection anchor from the soil again the moment it has lost its function. We not only remove the old materials from the soil, but reapply them in a subsequent project. This is not only financially interesting, but also contributes significantly to reducing CO2-emissions on a project."
H5s was contracted by construction consortium BAAK to install the temporary and permanent anchors on the north side of the Maas Delta tunnel. Bongers: "Due to varying soil compositions, which could only be investigated further during the start of the work, we jointly optimized and calculated the intended anchoring structures. This meant that some of the planned strand anchors were replaced by horizontally drilled SSI anchors. Indeed, due to the poor foundation, the requested anchor force could not be mobilized by the soil."
H5s installed a total of 434 temporary strand anchors and 257 permanent strand anchors, including the supply and fixing of the anchor chair assembly. "The strand anchors consist of 9 to 17 strands in varying lengths from 45 to 70 meters," Bongers explained. "In the first period of the project, the time pressure was so great that we started with three anchor assemblies to meet the requested schedule. We worked pleasantly and constructively with the team at BAAK and thank them for their cooperation. We look forward to returning in 2021 to start making the last hundred final anchors."
