Analisi stabilità "Madonna deIn geotechnical field, the Limit Equilibrium Method (LEM) is one of the most used analysis to solve the stability problem of an unstable rock cliff. A limit of the LEM is the impossibility of considering the evolution over the time of the rock’s mechanical parameters and also the effect of the crack tip stress concentrations, which may trigger a crack propagation. The aim of this thesis is to overcome these limitations of the LEM model, proposing the application of a fracture mechanism approach on the real unstable rock mass of “Madonna del Sasso”. In this thesis, the effects of degradation of rock joint are evaluated through a time-dependent reduction of rock bridge along the discontinuity.