In the past it was virtually impossible to verify if sheet piles were indeed driven to the required depth. Nowadays the trusty Cone Penetration Technique comes to the rescue in the form of a triaxial magnetometer that can be pushed into the ground by means of a CPT penetrometer pusher.
The magnetometer measures the differences in the magnetic field in its direct vicinity. This makes it not only an excellent tool for the detection of UXO’s, but also for the inspection of sheet piles in place.
In the picture you see the inspection works been carried out by Dutch specialist Bouw- en Managementservice Nederland.