Criteria for rapid sliding II.: thermo-hydro-mechanical and scale effects in Vaiont case

Abstract

Thermally induced excess pore pressures have been included into a two-wedge evolutive model of Vaiont landslide. The problem requires the solution of a system of four coupled balance equations for the shear bands and the surrounding rock as well as the joint equation of motion of the entire slide. The model predicts the high velocities observed and is consistent with other data (slide geometry, residual strength, and conditions on the sliding surface). The interpretation of a sensitivity analysis suggests that there exists a threshold permeability band, in the range 10- 8 to 10- 10 m/s, which separates potentially fast motions from slow motions. This conclusion is maintained if the scale of the landslide is reduced.