Discontinuity Characterization of Rock Masses through Terrestrial Laser Scanner and Unmanned Aerial Vehicle Techniques Aimed at Slope Stability Assessment

Abstract

Stabilization projects of rock masses cannot be performed without a proper geomechanical characterization. The classical approaches, due to logistic issues, typically are not able to cover extensively the areas under study. Geo-structural analysis on point cloud from terrestrial laser scanning and photogrammetry from unmanned aerial vehicles are valid tools for analysis of discontinuity systems. Such methodologies provide reliable data even in complex environmental settings (active cliffs) or at inaccessible sites (excavation fronts in tunnels), offering advantages in terms of both safety of the operators and economic and time issues. We present the implementation of these techniques at a tuff cliff over the Santa Caterina beach (Campania) and at the main entrance of Castellana Caves (Apulia). In the first case study, we also perform an integration of the two techniques. Both sites are of significant tourist and economic value, and present instability conditions common to wide areas of southern Italy: namely, retrogressive evolution of active cliffs along the coast, and instability at the rims of natural and/or artificial sinkholes. The results show the reliability of the data obtained through semi-automatic methods to extract the discontinuity sets from the point clouds, and their agreement with data collected in the field through classical approaches. Advantages and drawbacks of the techniques are illustrated and discussed.

Combined Use of Aerial Photogrammetry and Terrestrial Laser Scanning for Detecting Geomorphological Changes in Hornsund, Svalbard

“…Fine cloud-to-cloud registration was performed by a Multi-Station Adjustment (MSA) tool in RiSCAN Pro [32]. The software identifies common plane patches from different scan positions, links them together and minimizes the errors between all these linked plane patches by using an iterative matching algorithm [41].…”

“…The integration of 3D modeling techniques is advantageous for obtaining the most complete and useful object coverage for many application areas [19]. Integration of aircraftbased, helicopter-based and UAV photogrammetry with TLS is popular, especially at large or inaccessible sites [21,23,[30][31][32]. In this paper, digital aerial photogrammetry and TLS were combined to produce a continuous DEM with the highest possible resolution and accuracy.…”

Building stone quarries: resource evaluation by block modelling and unmanned aerial photogrammetric surveys

“…The acquired images allow processing of detailed digital surface models (DSMs), orthophotos, and three-dimensional (3D) models (Egels and Kasser 2001). These data can be used in commercial terms to calculate the yield, volume of waste and for analysis of stability, and stress distribution, among other applications (Wang et al 2019a, b;Török et al 2020;Pagano et al 2020;Duarte et al 2020;Akara et al 2020).…”

Three-Dimensional Laser Scanning-Based Method for Identifying Rock Discontinuities

“…The extraction of rock discontinuities with 3D-LS generally has two steps: (1) detecting discontinuities and extracting geometric parameters and (2) registering and georeferencing multisite cloud data (Hu et al, 2019b;Pagano et al, 2020). Acquiring highquality 3D-LS point cloud data and preprocessing the point cloud are indispensable requirements.…”