Understanding the instability mechanisms of chalk mines in presence of water (France)

Vincent Renaud (1) , Auxane Cherkaoui (1) , Jean-Marc Watelet (1) , Philippe Gombert (1) , Charles Kreziak (2)

1 INERIS - Institut National de l'Environnement Industriel et des Risques
2 Cerema Direction Ile-de-France - Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement - Direction Ile-de-France

In January 1910, the 100-year flood of the Loing River caused the tragic collapse of an underground chalk mine at Château-Landon (France), which resulted in the death of 7 people. In this valley, three other underground chalk mines had already collapsed. The hydrogeological analysis of the site and the geomechanical studies carried out on the chalk enabled to elaborate a 3-stage collapse scenario: (1) exceptional rainfall generating intense flooding of the Loing, which plays the role of a hydraulic dam and causes (2) a rise of the chalk aquifer, which invades (3) the lower parts of the mine and weakens the pillars until they collapse. To evaluate this scenario, the Royer mine, the last underground mine still intact in this sector, was thoroughly studied. This study included a complete 3D scan of the mine, modelling of its geomechanical behavior and geomechanical and hydrogeological monitoring that will last several years.

Domains: Applied geology; Risques

Vincent Renaud, Auxane Cherkaoui, Jean-Marc Watelet, Philippe Gombert, Charles Kreziak. Understanding the instability mechanisms of chalk mines in presence of water (France). 14th International Congress on Rock Mechanics and Rock Engineering (ISRM 2019), Sep 2019, Foz do Iguassu, Brazil. pp.2532-2539. ⟨ineris-03237767⟩