Numerical analysis of the life-time of an abandoned gypsum mine

A numerical analysis of the evolution with time of an abandoned gypsum mine flooded by water is presented. The lay-out of the problem is shown first, together with the experimental results obtained in laboratory tests on gypsum specimens retrieved from site. An elastic-plastic strain-hardening constitutive model, capable of taking weathering effects into account, is sketched next. A chemo-mechanical analysis of the progressive dissolution of a gypsum pillar in contact with water is then presented. It is shown that it is possible to describe the dissolution process until pillar failure under the action of the overburden is achieved. The remaining life-time of the abandoned mine can be therefore estimated and a decision about the possible remedial measures taken on the basis of rational considerations.