The contractor who installed them is not to blame. But what now? Get those poles out again! The problem was that the concrete piles had gone through the bottom layer of clay and were now standing with their feet in an aquifer, a ground layer from which drinking water is extracted. To have to demolish everything again would be a disaster for the owner.
Ultimately, Van Schie was called in because of their knowledge in the field of bentonite. Together with a consultancy firm from Breukelen, a plan was drawn up that the municipality agreed to. Liquid bentonite was now fed to the bottom of each post via a long, thin lance, where the substance settled around the feet of the posts and thus formed a sealing layer against leakage.
Bentonite is a natural product, a type of clay that immediately expands as soon as it comes into contact with water. It consists of sodium particles that are so small that they can make the soil waterproof. Therefore, it is widely used in drilling and sealing work.
