Geo-mechanical characterization of carbonate rock masses by means of laser scanner technique

Knowledge of the geometrical and structural setting of rock masses is crucial to the stability and to design the most suitable stabilization works. In this work we use Terrestrial Laser Scanning (TLS) at the site of the Grave of the Castellana Caves, a famous cave in southern Italy. The Grave is the natural access to the cave system, produced by of the vault, due to upward progression of instabilities in the carbonate rock masses. It about 55-m high, bell-shaped, with maximum width of 120 m. Aim of the work is the of carbonate rock masses from the structural and geo-mechanical standpoints the use of innovative survey techniques. TLS survey provides a product consisting of of geo-referenced points, to be managed in space, to become a suitable database for morphological and geological-structural analysis. Studying by means of TLS a rock face, inaccessible or located in very complex environments, allows to investigate slopes in overall areal extent, thus offering advantages both as regards safety of the workers and needed for the survey. In addition to TLS, the traditional approach was also followed by scanlines surveys along the rims of the Grave, following the ISRM for characterization of discontinuity in rock masses. A quantitative among the data obtained by TLS technique and those deriving from the classical -mechanical survey is eventually presented, to discuss potentiality of drawbacks of the techniques used for surveying the rock masses.