Thermal effects in landslide mobility

Abstract

The paper describes a thermo-hydro-mechanical formulation to model thermally induced effects due to the irreversible work input generated during soil deformation. The model was implemented into a material point calculation procedure. The method is applied to the analysis of landslides. A simple slope stability is first analysed. Mechanical work essentially dissipates in shearing bands, which develop excess pore water pressures. The marked effect of soil permeability to control the slide motion after failure is described. Shear band thickness is also a relevant control variable. The problem posed by the non-realistic thickness of shear bands in numerical calculation is addressed by means of a numerical procedure that includes consideration of embedded shear bands where the strains are assumed to be localised. Balance equations describing local flow and thermal interactions between shear bands and the remaining material are formulated. The method is applied to model the instability and subsequent rapid motion of Vajont landslide. Calculated run-out and sliding velocity reproduce, in a satisfactory manner, field observations.