Soil characterization from monitoring of a steep slope in layered granular volcanic deposits

The first results of high temporal resolution hydrological monitoring of a steep slope, covered with layered loose pyroclastic deposits, are presented. The collected data of soil water content and suction, which allow estimating the water retention curves experienced in the field by the soil belonging to layers of different hydraulic characteristics, indicate that field monitoring is of paramount importance to correctly model the complex hydrological response of layered slopes in pyroclastic soils. In fact, the obtained retention curves significantly differ from those obtained in laboratory with standard tests over small undisturbed specimens. Conversely, a substantial agreement between retention data from field monitoring and from flume infiltration experiments is found, thus confirming the validity of flume experiments with small scale slopes for the investigation of slope failure mechanics.