Softening and swelling mechanism affecting south slope of Civita di Bagnoregio (VT)

Civita di Bagnoregio is a small village in Central Italy, located on the top of a hill and affected by landslides that are progressively reducing the urban area. The access consists of a pedestrian bridge that connects Bagnoregio municipality to the village. The south slope beneath the bridge, is involved by frequent instability phenomena. This work describes the analysis carried out and it aimed at the definitions of geological and geotechnical mechanism affecting the above mentioned slope. A geotechnical survey has been carried out. These surveys showed the presence of a superficial layer, resulting from the softening and swelling of underlying clay-silty strongly overconsolidated, responsible for the superficial landslide phenomena. A slope stability and a 3D laser scanner model has been carried out. The analysis demonstrates that a correct design for the landscape preservation and consolidation of unstable towns needs an understanding of triggering mechanism and geotechnical properties of the involved soils. © 2013 Taylor & Francis Group, London.