Monitoring of pore pressures in fine-grained landslide debris covers in southern Italy

摘要

The paper deals with a study conducted on the southern portion of the Apennine fore-deep, where slopes with outcrops of 20-25 m-thick groundwater-hosting debris covers, most of which originating from landslides, were identified. Ground-waterflow is irregular, depending on geometry and mode of formation of the hosting debris covers. Recurrence of landslides (return period of approximately 10 years) on these debris covers induces instability in upslope areas, causing significant damage to the local historical villages. The use of hydrological-statistical and deterministic models made it possible to compute rainfall threshold values whose exceedance might reactivate landslides. The models also evidenced the need for validating landslide-triggering assumptions via the collection of additional field data. Data gathered during the first 4 years of operation of a local rainfall and pore pressure monitoring station substantiated some of the findings resulting from the modelling of landslide reactivation factors. The data also highlighted the complexity of local processes of seepage and ground-waterflow. As a result, further experimental data are required to implement a model that correlates rainfall and pore pressure changes with landslide initiation.