At the end of August 2023, our soil investigators carried out 11 cone penetration tests down to a depth of 30 metres at a location in Amsterdam that was contaminated. After this work was carried out, the probes were sealed using bentonite, as we were carrying out these tests on a dam.

On (dike) bodies that have to hold back water there is a protection area where such cone penetration testing cannot be carried out unless the probe holes are sealed afterwards. The zones are meant to protect the (dike) bodies to avoid piping. Piping means that a water flow can arise under the dam, which can cause a larger hole to form until the dam collapses. This must, of course, be avoided.

This cone penetration testing project was a good learning experience for the soil investigators involved, in part due to all the safety measures regarding the contamination at the site. There was, for example, a decontamination unit and a safety professional from the ACTA group, and the cone penetration testing truck had to be cleaned at the site.