Stability analysis of “Grotta delle Felci” cliff (Capri Island, Italy): structural, engineering-geological, photogrammetric surveys and laser scanning

A study of rock slope stability was performed using geological surveys and Digital Terrestrial Photogrammetry (DTP) integrated by Laser Scanning (LS) and topographic measurements. The use of DTP is useful especially in inaccessible sites such as natural cliffs. By obtaining oriented stereo images, accurate digital surface models and orthophotos, useful data can be produced showing geometrical characteristics of joints, blocks and slopes such as planes attitude, spacing, persistence and rock mass volumes. In order to accomplish the analysis, DTP was combined with LS in order to build the Digital Dense Surface Model (DDSM) of the slope. The conventional method of limit equilibrium was applied to study the slope stability using a deterministic approach and to suggest activities of geo-monitoring and engineering solutions for risk mitigation with respect to the environment.