Multiphysical modelling for thermo-mechanical behaviour of rock masses in slope-scale gravitational dynamics

Volcanic and glacial valley systems are geological context where Deep Seated Gravitational Slope Deformations (DSGSDs) frequently evolve. These areas experienced in their geological history significant variation in stress field due to the rapid growth of volcano flanks or glacial debuttressing rebound, respectively. In addition to these effects, a less importance have been given to multi-physical interactions between the slopes and the natural systems in which the DSGSD can evolved. In order to evaluate the role of physical or multi-physical interaction in dictating time-dependant slope-scale gravitational deformation processes, a numerical analysis has been approached reproducing by stress-strain and thermo-hydrodynamical modelling, the mutual interaction between thermal and mechanical processes in slope stability. With the purpose to evaluate and constrain the inner forcings related to deep systems which can influence the gravitational process acting in the slopes, the combination of models at different geometric-scales have been experimented. Basing on two selected case study, representative of two thermal end-member (i.e. warm and cold systems) the influence of thermo-mechanical processes in gravity-induced deformations was evaluated by adopting different solving schemes as function of the stationarity or transiency of the systems within an observation time-window. Coupled or Uncoupled solution between two or more physics were experimented reproducing sequential evolution of slope system with the support of FDM and FEM numerical codes. A process of validation of the Thermal and the Mechanical models defined for both deep- and slope-scales were achieved by means of sensitivity and parametric analysis. The validated models were then used for the formulation of physically-based scenarios, defined to evaluate the role of multiple factors in the onset or time-evolution of slope deformation. The adopted approach represented an useful tool to evaluate the proneness of DSGSDS to paroxysmal tertiary failure and in the definition multi-hazard scenarios related to slope instabilities