Terrestrial laser scanning of rock slope instabilities

While terrestrial laser scanning and photogrammetry provide high quality point cloud data that can be used for rock slope monitoring, their increased use has overwhelmed current data analysis methodologies. Accordingly, point cloud processing workflows have previously been developed to automate many processes, including point cloud alignment, generation of change maps and clustering. However, for more specialized rock slope analyses (e.g., generating a rockfall database), the creation of more specialized processing routines and algorithms is necessary. More specialized algorithms include the reconstruction of rockfall volumes from clusters and points and automatic classification of those volumes are both processing steps required to automate the generation of a rockfall database. We propose a workflow that can automate all steps of the point cloud processing workflow. In this study, we detail adaptions to commonly used algorithms for rockfall monitoring use cases, such as Multiscale Model to Model Cloud Comparison (M3C2). This workflow details the entire processing pipeline for rockfall database generation using terrestrial laser scanning.

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The Implications of M3C2 Projection Diameter on 3D Semi-Automated Rockfall Extraction from Sequential Terrestrial Laser Scanning Point Clouds

Remote Sensing ◽

10.3390/rs12111885 ◽

2020 ◽

Vol 12 (11) ◽

pp. 1885 ◽

Cited By ~ 3

Author(s):

Paul-Mark DiFrancesco ◽

David Bonneau ◽

D. Jean Hutchinson

Keyword(s):

Laser Scanning ◽

Rock Slope ◽

Spatial Information ◽

Three Dimensional ◽

Terrestrial Laser Scanning ◽

Point Clouds ◽

Multiscale Model ◽

Computation Method ◽

Highly Active ◽

Optimal Projection

Rockfall inventories are essential to quantify a rockfall activity and characterize the hazard. Terrestrial laser scanning and advancements in processing algorithms have resulted in three-dimensional (3D) semi-automatic extraction of rockfall events, permitting detailed observations of evolving rock masses. Currently, multiscale model-to-model cloud comparison (M3C2) is the most widely used distance computation method used in the geosciences to evaluate 3D changing features, considering the time-sequential spatial information contained in point clouds. M3C2 operates by computing distances using points that are captured within a projected search cylinder, which is locally oriented. In this work, we evaluated the effect of M3C2 projection diameter on the extraction of 3D rockfalls and the resulting implications on rockfall volume and shape. Six rockfall inventories were developed for a highly active rock slope, each utilizing a different projection diameter which ranged from two to ten times the point spacing. The results indicate that the greatest amount of change is extracted using an M3C2 projection diameter equal to, or slightly larger than, the point spacing, depending on the variation in point spacing. When the M3C2 projection diameter becomes larger than the changing area on the rock slope, the change cannot be identified and extracted. Inventory summaries and illustrations depict the influence of spatial averaging on the semi-automated rockfall extraction, and suggestions are made for selecting the optimal projection diameter. Recommendations are made to improve the methods used to semi-automatically extract rockfall from sequential point clouds.

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SfM-MVS Photogrammetry for Rockfall Analysis and Hazard Assessment Along the Ancient Roman Via Flaminia Road at the Furlo Gorge (Italy)

ISPRS International Journal of Geo-Information ◽

10.3390/ijgi8080325 ◽

2019 ◽

Vol 8 (8) ◽

pp. 325 ◽

Cited By ~ 8

Author(s):

Vanneschi ◽

Camillo ◽

Aiello ◽

Bonciani ◽

Salvini

Keyword(s):

Laser Scanning ◽

Rock Slope ◽

Terrestrial Laser Scanning ◽

Rockfall Hazard ◽

Analysis And Design ◽

The World ◽

3D Software ◽

Steep Slopes ◽

3D Problem ◽

Potential Use

Rockfall events represent significant hazards for areas characterized by high and steep slopes and therefore effective mitigation controls are essential to control their effect. There are a lot of examples all over the world of anthropic areas at risk because of their proximity to a rock slope. A rockfall runout analysis is a typical 3D problem, but for many years, because of the lack of specific software, powerful computers, and economic reasons, a 2D approach was normally adopted. However, in recent years the use of 3D software has become quite widespread and different runout working approaches have been developed. The contribution and potential use of photogrammetry in this context is undoubtedly great. This paper describes the application of a 3D hybrid working approach, which considers the integrated use of traditional geological methods, Terrestrial Laser Scanning, and drone based Digital Photogrammetry. Such approach was undertaken in order to perform the study of rockfall runout and geological hazard in a natural slope in Italy in correspondence of an archaeological area. Results show the rockfall hazard in the study area and highlights the importance of using photogrammetry for the correct and complete geometrical reconstruction of slope, joints, and block geometries, which is essential for the analysis and design of proper remediation measures.

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APPLICATION OF TERRESTRIAL LASER SCANNING (LIDAR) IN ROCK SLOPE STABILITY. ΑΝ ΕXAMPLE FROM NORTHERN GREECE

Bulletin of the Geological Society of Greece ◽

10.12681/bgsg.11763 ◽

2017 ◽

Vol 50 (2) ◽

pp. 586

Author(s):

G. Ampatzi ◽

N. Chatzigogos ◽

M. Makedon ◽

G. Papathanassiou ◽

V. Marinos

Keyword(s):

Laser Scanning ◽

Rock Slope ◽

Failure Mechanisms ◽

Terrestrial Laser Scanning ◽

Structural Features ◽

Rock Slope Stability ◽

3D Mapping ◽

Remedial Measures ◽

Northern Greece ◽

Scanning Lidar

The scope of this study is to investigate the failure mechanisms of the eastern coastal zone of Mount Athos, using the LiDar device for the 3D mapping of the structural features of the rock mass. Therefore emphasis was given to the study of the planes of discontinuities that can trigger potential failures. All slopes were scanned by LiDar device in order to capture their structure and especially the orientation and the spacing of the discontinuities. The data were processed in order to produce the microtectonic model of the slopes and evaluate the potential slope failures. Finally some remedial measures are proposed.The results and the reliability as well as the constrictions of the applied methodology are discussed for future applications.

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