An annual cycle of loose rock flux on a large slope affecting a railway corridor, from serial LiDAR data in the White Canyon of the Thompson River, BC

Dave Gauthier, Matt Lato, Tom Edwards, D. Jean Hutchinson

In the proceedings of: GeoMontréal 2013: 66th Canadian Geotechnical Conference; 11th joint with IAH-CNC

Session: Transportation Geotechnique

ABSTRACT: The natural and cut slopes of White Canyon of the Thompson River, BC, adjacent to the Canadian National Railway line, present rock hazard problems not tractable by traditional kinematic or modeling approaches. The rock mass on the slope is highly weathered and fragmented, and multiple, complex failure modes may be occurring at any given time. During 2012 and 2013, we collected serial long-range LiDAR datasets spanning one calendar year, with the intention of documenting the flux of loose rock material (fallen discrete blocks and colluvium) and around the slope. The goal was to observe the movements of loose fragments on the slope, prior to reaching the rail line. We compared the serial LiDAR scans quantitatively, and observed two main displacement modes: bulk rock slide or fall, with large block failures; and discrete fragment flux from the upper face into mid-slope gullies, and later en masse debris movements to rail level. We have analyzed these observations in terms of mechanics, causes, and triggers of the movements, and recommend future studies to determine the appropriate frequency of observations required to leverage this method within monitoring and/or inspection programs. R…SUM… Les pentes naturelles et la coupe de White Canyon de la rivi‘re Thompson, C.-B., ‹ cŽt” de la voie ferr”e du Canadien National, pr”sente des probl‘mes d'al”a de rock pas traitables par des approches cin”matiques ou de mod”lisation traditionnels. La masse rocheuse sur le versant est fortement alt”r”e et fragment”e et multiple, des modes de d”faillance complexes peuvent se produire ‹ n'importe quel moment donn”. En 2012 et 2013, nous avons recueilli des ensembles de donn”es LiDAR ‹ long terme de s”rie couvrant une ann”e civile, dans le but de documenter le flux de mat”riau rocheux autour de la pente. L'objectif ”tait d'observer les mouvements des fragments d”tach”s sur la pente, avant d'atteindre la ligne de chemin de fer. Nous avons compar” les scans LiDAR s”rie quantitativement, et observ” deux principaux modes de d”placement: ”boulement en vrac ou ‹ l'automne, avec de grandes pannes de blocs, et le flux de fragment discret de la face sup”rieure dans les ravines ‹ mi-pente, et plus tard une salle de mouvements de d”bris masse au niveau du rail. Nous avons analys” ces observations en termes de m”canique, les causes et les d”clencheurs des mouvements, et de recommander des ”tudes futures afin de d”terminer la fr”quence appropri”e d'observations n”cessaires pour tirer parti de cette m”thode dans la surveillance et / ou des programmes d'inspection.

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Cite this article:
Dave Gauthier; Matt Lato; Tom Edwards; D. Jean Hutchinson (2013) An annual cycle of loose rock flux on a large slope affecting a railway corridor, from serial LiDAR data in the White Canyon of the Thompson River, BC in GEO2013. Ottawa, Ontario: Canadian Geotechnical Society.

@article{GeoMon2013Paper355,author = Dave Gauthier; Matt Lato; Tom Edwards; D. Jean Hutchinson,title = An annual cycle of loose rock flux on a large slope affecting a railway corridor, from serial LiDAR data in the White Canyon of the Thompson River, BC,year = 2013}