In most contexts where gypsum is present beneath the ground surface, dissolution mechanisms can occur and lead to the creation of underground voids. Whenever the geomechanical conditions are conducive, the destabilisation of such cavities can lead to severe ground movements on land surface like collapses, with potentially significant consequences for existing issues or to be considered for future developments. The understanding of the mechanisms and their translation in terms of hazard are defined through a methodology applicable to all gypsum contexts. In order to prevent the risks associated with these phenomena, prevention, mitigation and protection measures are proposed.
This guide, produced jointly by Ineris and Cerema for public authorities, is intended for stakeholders who must manage the risk linked to gypsum dissolution processes. It is mainly based on expert research carried out by Ineris and Cerema over several years.