Assessing the Capability and Limitations of ALS, TLS and Terrestrial Photogrammetry for Mapping Differential Slope Change in Mountainous Terrain

M. Lato, D. Gauthier, D.J. Hutchinson, T. Edwards

In the proceedings of: GeoRegina 2014: 67th Canadian Geotechnical Conference

Session: Transportation Geotechnics

ABSTRACT: Assessing transportation corridors exposed to the hazard of rockfalls and rockslides traditionally involves mapping and measuring physical characteristics of the visible cut or natural slope face. Conducting this form of traditional rockfall hazard analysis is extremely challenging in mountainous terrain where site accessibility is often limited, visibility is obstructed or minimal, and the terrain is extremely complex. Using 3D remote sensing data collected at different points in time enables the monitoring of differential slope change processes, which can be used to track rockfall frequency and magnitude. This information can be critical in assessing a transportation corridor for risk from natural threats. The advantages and limitations of different technologies and when they should optimally be deployed is not widely published or clearly defined. Between December 2012 and December 2013 the efficacy of three remote sensing technologies were compared for detecting natural and anthropogenic changes at a location along the CN railway, in British Columbia, Canada. The results demonstrate the ability to map topographical change with all three technologies, and the limitations/weaknesses of each technology with respect to mapping change. RÉSUMÉ Évaluation des corridors de transport exposés à des risques de chutes de pierres et éboulements implique traditionnellement la cartographie et la mesure des caractéristiques physiques de la coupe visible ou face de la pente naturelle. La réalisation de cette forme d'analyse traditionnelle des risques de chutes de pierres est extrêmement difficile en terrain montagneux où l'accessibilité du site est souvent limitée, la visibilité est obstruée ou minime, et le terrain est extrêmement complexe. En utilisant des données de télédétection recueillies 3D à différents points dans le temps permet la surveillance des processus différentiels de changement de pente, qui peut être utilisé pour suivre la fréquence et l'ampleur des chutes de pierres. Cette information peut être critique dans l'évaluation d'un corridor de transport pour le risque de menaces naturelles. Les avantages et les limites des différentes technologies et quand ils doivent être déployées de manière optimale n'est pas largement diffusés ou clairement définis. Entre Décembre 2012 et Décembre 2013, le efficacité de trois technologies de télédétection ont été comparées pour détecter des changements naturels et anthropiques à un emplacement le long de la voie ferrée du CN, en Colombie-Britannique, Canada. Les résultats démontrent la capacité de la carte topographique avec changement tous les trois technologies, et les limitations / faiblesses de chaque technologie en ce qui concerne le changement de la cartographie. 1 INTRODUCTION Transportation corridors in mountainous and other steep, rocky terrain are routinely subject to natural hazards, which threaten physical infrastructure, the safety of workers, travelers, and the delivery of shipped goods. The Trans-Canada Highway #1 (TCH), and CN and CP railways traverse the Coast Mountains, following the Thompson and Fraser River valleys. There, the transportation corridors are subject to multiple hazards including rockfalls, rockslides, landslides, debris flows, and snow avalanches (e.g. VanDine, 1985; Hungr et al., 1999). Hungr et al. (1999) studied the frequency and magnitude of historical rockfall hazards observed along highway and railway corridors in southwestern BC. For the assessment of rockfall hazard potential and the associated risk of derailment, CN Rail employs the ‚Rockfall Hazard Risk Assessment' (RHRA) (Abbott et al. 1998a, 1998b). This system relies on the ability of the assessor to see a source zone from track level (Pritchard et al., 2005). In areas of steep or rugged terrain, rockfall source zones are obscured and cannot be assessed with this method. The ability to map change associated with rockfall and slope movement is a topic of interest to the railway companies as it will help to understand rockfall activity levels and for the purpose of risk mitigation. Recent technological advances in the field of remote sensing and 3-dimensional (3D) data interpretation have enabled geotechnical engineers to understand natural and anthropogenic slope processes at unprecedented

RÉSUMÉ: SING THE CAPABILITY AND LIMITATIONS OF ALS, TLS AND TERRESTRIAL PHOTOGRAMMETRY

Access this article:
Canadian Geotechnical Society members can access to this article, along with all other Canadian Geotechnical Conference proceedings, in the Member Area. Conference proceedings are also available in many libraries.

Cite this article:
M. Lato; D. Gauthier; D.J. Hutchinson; T. Edwards (2014) Assessing the Capability and Limitations of ALS, TLS and Terrestrial Photogrammetry for Mapping Differential Slope Change in Mountainous Terrain in GEO2014. Ottawa, Ontario: Canadian Geotechnical Society.

@article{GeoRegina14Paper360,author = M. Lato; D. Gauthier; D.J. Hutchinson; T. Edwards,title = Assessing the Capability and Limitations of ALS, TLS and Terrestrial Photogrammetry for Mapping Differential Slope Change in Mountainous Terrain,year = 2014}