Hydraulic hysteresis of unsaturated pyroclastic soils: experimental investigation and model calibration

In many geotechnical applications, especially in the study of weather-induced landslides, a reliable soil hydraulic characterization under unsaturated conditions is required. Currently, the experimental techniques neglecting hydraulic hysteresis represent the greatest limitation to landslide forecasting. Here, experimental data from a new procedure to obtain an unsaturated soil hydraulic characterization are reported. These allows us to evaluate the soil hydraulic properties not only along the main drying path but also along wetting/drying cycles. Pyroclastic soil samples collected at a test site located at Mount Faito in the Campania region (southern Italy) were tested. The experimental investigation consisted of a forced evaporation test followed by a number of wetting-drying cycles.