UAV, Virtual and Augmented reality tools and geotechnical modeling, an integrated approach for improved landslide risk mitigation strategies.

The use of Unmanned Aerial Vehicles (UAVs) has become a fundamental technique in engineering geology, enabling safer and more accurate geological surveys, making possible to conduct virtual geomechanical surveys in areas that are hazardous for traditional fieldwork. This study presents an integrated methodology that combines UAV-based photogrammetry and LiDAR with advanced analytical techniques for 3D geotechnical modelling. The proposed workflow includes UAV data acquisition, 3D model generation, virtual structural analysis, 2D and 3D geotechnical modelling, runout analysis, and the development of virtual and augmented reality slope models. A comparison between the nadiral LiDAR derivate DTM and the oblique photogrammetric model demonstrates that in steep slope the nadiral DTM tends to hide overhanging geometries; a fundamental limitation in evaluating the slope stability. The approach demonstrates the effectiveness of UAV-derived data in improving slope geometry representation, rock mass characterization, and landslide risk assessment.