Back-analysis of rock landslides to infer rheological parameters

This chapter focuses on the description of a multidisciplinary methodology aimed at a comprehensive modeling of large rock slope instabilities, by considering the rheological behavior of the involved rock masses. Such a methodology is characterized by an integrated approach addressed to take into account the complex set of variables that features rock slope instabilities occurring on a wide range of spatial/ temporal scales. Large rock slope failures can be regarded as the paroxysmal phase of time-dependent gravitational processes influenced by several factors that can be grouped in predisposing and conditioning ones. The predisposing factors encompass geological-structural setting and geomechanical properties, the conditioning factors act at different scales and are related to morpho-evolution of slope-to-valley floor systems, due to both surface effects of tectonic deformations and erosional/depositional processes, as well as geodynamic stress regime variations. In addition, triggering factors can be referred to intense and short-duration actions that, among the others, can be related to earthquakes, water pressure changes and anthropic activities. The here illustrated methodology consists in a multi-modeling approach that includes the contributions of a morpho-evolutionary modeling of the slope-to-valley floor system; a detailed engineering-geology modeling, that transposes geomechanical parameters to geological-structural features of; a time-dependent stress-strain numerical modeling, performed through a sequential approach which takes into account the main morph-evolutionary stages of the slope. Two case studies are here presented from the Italian Apennines which experienced such a multi-modeling approach to infer suitable rheological parameters to rock masses involved in creep process on natural slopes.