Analysis of the Effects of Seasonal Pore Pressure Variations on the Slope Stability Through Advanced Numerical Modelling

The paper presents novel results from the advanced numerical modelling of the effect of cycling pore water pressures on landslide processes. It combines the stability analysis of a prototype natural slope through a hydro-mechanical nonlinear finite element approach with the calibration of a kinematic hardening model against representative laboratory data, to draw conclusions of significance to both researchers and designers. The analyses have been carried out for two permanent hydraulic steady-state conditions representing the average pore water pressure regime at the end of the winter and summer season, thus replicating in a simplified way the seasonal fluctuations of the piezometric levels resulting from transient seepage processes generated by the slope-atmosphere interaction. The work shows the ability of the constitutive law, seldom used in these kind of analyses, to predict a progressive accumulation of plastic deformations during the cyclic fluctuation of pore water pressures associated to climate. More importantly, the output of the advanced modelling are useful to support the phenomenological interpretation of the landslide processes associated to natural hazards and to provide guidance for the sustainable management of marginally stable slopes affected by a constant evolution of permanent displacements.