HET = Hole Erosion Test vs. JET = Jet Erosion Test

As most hydraulic structure failures are attributed to internal erosion, the Flanders Hydraulics Research (FHR) centre in Flanders, Belgium, wanted tools to assess the safety of the Scheldt’s sea and river dykes, as well as the project to reinforce and raise these dykes.

Stéphane Bonelli and Sylvie Nicaise from the RECOVER unit were asked to coordinate the erosion tests. The experimental tests were carried out in the Geomechanics laboratory of the RECOVER unit and in the field in Belgium. They were carried out on different test benches depending on their type, e.g. JET for overflow, HET for conduit erosion, CET for contact erosion, etc. The conclusions validated the choice of tools adapted to the different constraints.

These tools, which improve the analysis of the risk of internal erosion, meet an expectation and are likely to lead to international development.
This expertise was incorporated into the FHR projects on the Scheldt dykes following the report on the vulnerability of dyke soil to internal and surface erosion. HET: Hole Erosion Test was developed by Irstea JET: Jet Erosion Test is part of the ASTM1 D5852 standard (withdrawn in 2016)