The project was carried out for Siemens at the site of a new gas-fired power station in Herne. Over 1300 foundation pile locations were screened for UXO and cleared down to 15m below ground level without affecting other site preparation activities.
In Germany, any areas that suffered bombing during the Second World War must have a UXO site survey before construction can begin. Conventional survey methods involve drilling boreholes that create ground disturbance, which is intrusive and expensive to remediate. Fugro’s UXO screening system is based on a magnetometer located behind a standard CPT cone.
The system is designed to allow quick and deep penetration with only minimal ground disturbance. The Magcone delivers a log of the magnetic field with depth and is monitored in real-time; if any magnetic anomalies are observed ahead of the probe then probing is stopped for excavation.
“We are impressed with Fugro’s UXO solution, especially the flexibility of using it in parallel with ongoing site-levelling activities and its accuracy in detecting ferromagnetic anomalies at depths up to 15m,” said Siemens construction manager Kevin Engelking. “All ferromagnetic objects detected were excavated for verification and approved by the relevant authorities. This allowed us to quickly clear the entire site, maintain our construction schedule and safely install the foundation piles for the power station.”
Got a story? Email news@theconstructionindex.co.uk
