Planning and Monitoring of Mitigation Measures in a Landslide-Affected Area Through Numerical Modelling, Conventional and Satellite Data

Abstract

Pisciotta village, located in the Southern part of Cilento, Vallo di Diano and Alburni National Park (Campania Region, Italy), is strongly affected by erosional and gravitational phenomena which cause severe damage to existing structures and infrastructures. In this paper, we describe the approach adopted to design and monitor stabilization interventions carried out on unstable sectors of the village. The preliminary geological and geomorphological characterization of the phenomena has led to plan a site-specific geotechnical investigations and monitoring system to assess the stability conditions of the slope. Geotechnical monitoring in pre-intervention phase benefitted of boreholes, successively equipped with piezometers and inclinometers, laboratory testing (triaxial test, shear stress test, etc.) and historical remote sensing data acquired in time-span 2011–2018 by COSMO-SkyMed constellation and processed by means of DInSAR technique have been used to assess the stability conditions. Thus, starting from the defined geotechnical model, a back-analysis slope stability test was performed to assess the safety condition of the slopes, referred to limit equilibrium condition along slip surface. Once validated the geotechnical model in failure condition, remedial works consisting in a drainage system and structural works (bulkhead of poles and retaining walls) have been designed. Finally, the efficacy of remedial works has been investigated by means of DInSAR data analysis. To provide the latter data, a network of passive corner reflectors was designed and deployed within the investigated area, thus obtaining the evolution analysis of post-intervention phase displacement time-series.