Collapse/subsidence : evolution of the overburden massivity according to the geomorphology in the Lorraine iron mines case

Abstract : This paper presents a methodology allowing to discriminate violent collapses of progressive subsidences from sixteen historical collapses and subsidences cases known in Lorraine. Initially, we will present the discrimination methodology. Using a geometrical criterion and a geological criterion, this methodology has allowed to discriminate violent collapses of progressive subsidences. Next we will approach, through energy balances resulting from large scale numerical modellings, the geomorphology effect on the mechanical behavior of overburden. The study of energy dissipations in the overburden shows that a valley and vertical fractures decrease the overburden massivity.