Integrated Remote Sensing and Geotechnical Modelling for the Stability Assessment of Structurally Complex Rock Masses with Natural Cavities

Abstract

Reliable stability assessment of structurally complex rock masses increasingly relies on advanced remote sensing techniques integrated with detailed geotechnical analysis. This study presents a combined remote geotechnical workflow applied to rock masses surrounding natural cavities, with the study area located in Greece, aiming to evaluate the stability of coupled cavity–slope systems under varying conditions. The methodology combines Unmanned Aerial Vehicle (UAV) photogrammetry and SLAM-based LiDAR surveying to acquire centimetre-scale surface and underground opening data. These datasets are fused into a geometrically consistent three-dimensional representation of the slope–portal–cavity system, enabling improved documentation of slope morphology, internal cave geometry and externally exposed discontinuity patterns. The fused spatial dataset was then used to extract a representative two-dimensional cavity–slope section for plane-strain finite element analysis. The numerical model was formulated as an equivalent-continuum model using the Hoek–Brown failure criterion, with stability assessed through the Shear Strength Reduction technique across multiple scenarios. Overall, the study demonstrates that integrated geotechnical and remote-sensing approaches improve geometric completeness and consistency, enhance reproducibility, and reduce geometry-related uncertainty in scenario-based stability assessments of complex rock masses with natural cavities and underground openings.