Deepening an old, verticalised pit: rock slope instability hazard assessment using a digitally augmented structural database (Flône limestone quarry, Belgium)

We present a rock slope instability hazard study of the Flône pit (Belgium) by means of a deterministic kinematic stability analysis. The specificity of this study resides in the “digital augmentation” of the field mapping structural database (x 5) by semi-automatic point cloud analysis. Results show that the main instability hazards in the actual pit are flexural toppling and, to a lesser extent, wedge sliding. Planar sliding, although minor, will constitute a significant hazard for interbench rupture during future excavation due to the presence of an anticline structure at depth. The augmented - and georeferenced - structural database has enabled us to generate a synthetic rock slope instability hazard map that constitutes the basis for the recommendation of targeted monitoring solutions during future excavation works.