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The 1889 rock slide along Champlain Street is the one that caused the largest number of fatalities in this area of Quebec City during the 19th century. This paper presents a historical retrospective of the events leading to the 1889 slide, starting with the 1841 slide in the same area, which was as significant. Mitigation measures were initiated mainly after 1880, but they were not sufficient to prevent the major catastrophe anticipated by those who did the investigation of the Cap Diamant, including Charles Baillairge. The story of the 1889 slide ends in 1894 by a judgment by the Supreme Court of Canada, in which the Queen was not held responsible for the consequences of the slide, although the main trigger was the water draining from the Citadel, from a damaged drain, into the cliff fissures. A back-analysis of the 1889 slide reached the same conclusions as Charles Baillairge: the 1889 slide was a topple. This paper also highlights the significant contribution of Charles Baillairge (1826-1906) in the understanding of rock slide processes along Cap Diamant. Le glissement rocheux de 1889 le long de la rue Champlain est celui qui a cause le plus de deces dans cette partie de la ville de Quebec au cours du 19e siecle. Cet article presente une retrospective historique des evenements qui ont mene a celui de 1889, et cela en commencant par un autre glissement rocheux survenu en 1841 dans le meme secteur, evenement aussi important que celui de 1889. Des mesures de prevention ont ete mises en place apres 1880 mais elles n'ont pas ete suffisantes pour prevenir la catastrophe de 1889 qui avait ete apprehendee par ceux, incluant Baillairge en 1880, qui avaient etudie le site du cap Diamant. La revue historique du glissement souligne le jugement de la Cour Supreme du Canada en 1894 qui conclut que la Reine ne pouvait etre tenue responsable des consequences du glissement malgre le fait qu'un drain defectueux aurait permis aux eaux de drainage de la Citadelle de s'infiltrer dans les larges fissures presentes dans le talus. Une retro-analyse du glissement de 1889 a permis d'appuyer le fait que le glissement etait un basculement. Cet article souligne la contribution de Charles Baillairge (1826-1906) a la comprehension des glissements de terrain le long du cap Diamant., Introduction Le promontoire de Quebec, de par sa position strategique le long du fleuve Saint-Laurent, est un des lieux les plus peint et photographie au Canada depuis le XVIIe siecle. [...]

The Black Lake rockslide is located on the east wall of an open-pit mine initially operated by LAB Chrysotile near Thetford Mines, Quebec. Movements were observed in July 2012 when a volume of 2.0 x [10.sup.7] [m.sup.3] was mobilized, destroying a large portion of Highway 112. Mining operations ceased in 2012, causing the complete shutdown of the pumping system whose goal was to prevent the rise of water level in the pit. As the water level increases in the pit, it is essential to determine the potential of tsunami generation by possible partially submerged rockslides and to understand the potential impacts. A series of possible scenarios have been analysed with regard to velocity and acceleration of the potential rockslide as well as the corresponding wave generation and inundation. Results from the simulation show that when the factor of safety of the global slope is less than unity, inundation would not reach the potentially vulnerable infrastructures. Maximum wave height will vary as a function of the filling of the lake, and the lower wave height relative to water depth will happen when the lake is completely filled.Key words: landslide-generated tsunami, partially submerged landslide, numerical modeling, open-pit mine, active rockslide.Le glissement de Black Lake est situe sur la paroi est d'une ancienne mine a ciel ouvert exploitee par la compagnie LAB Chrysotile, a Thetford Mines, Quebec. Ce glissement actif a connu un fort episode de glissements en juillet 2012, ou un volume de 2,0 x [10.sup.7] [m.sup.3] a ete mobilise, emportant une large portion de la Route 112. Les operations minieres ont cesse en 2012, causant l'arret complet du systeme de pompage lequel visait a prevenir la montee du niveau d'eau dans la fosse. Comme le niveau d'eau augmente dans la fosse il devient primordial de determiner le potentiel tsunamigenique genere par des glissements rocheux partiellement submerges possibles afin de comprendre le phenomene et de reagir efficacement a celui-ci. Plusieurs modelisations numeriques ont ete realisees a partir de scenarios probables concernant les vitesses et les accelerations de glissement rocheux potentiel ainsi que la formation de vagues et l'inondation correspondantes. Les modelisations effectuees ont permis de montrer que, lorsque le facteur de securite de la pente globale est inferieur a 1, aucune infrastructure potentiellement vulnerable ne serait touchee par un eventuel tsunami. La hauteur maximale de la vague generee sera fonction de la hauteur d'eau dans le bassin. Les hauteurs de vagues minimales, relatives au niveau d'eau dans le bassin, seront generees lorsque le bassin sera completement rempli.Mots-cles: tsunami genere par un glissement de terrain, glissement partiellement submerge, modelisation numerique, mine a ciel ouvert, glissement rocheux actif., 1. IntroductionApproximately 90 km south of Quebec City, on the border between Black Lake sector to the north (part of Thetford Mines) and the municipality of Saint-Joseph-de-Coleraine to the south, [...]

In recent years, several large open-pit mines have started operating in the province of Quebec in Canada, and some of the largest planned pits are located close to public infrastructure. Historically, large open-pit mining has seldom been done in many mining regions, such as the Abitibi region, where underground mines are the norm. As an integral part of achieving social acceptability of open-pit mining, the stability of mining slopes must be carefully analyzed during the design process and the presence of public infrastructure near the slopes must be adequately considered. The province of Quebec does not have specific guidelines regarding such design considerations. This paper provides a short overview of the literature on some current practices regarding mining slope design close to public infrastructure. To demonstrate its applicability in the Quebec provincial context, the paper then investigates the stability of the west wall of the LAB Chrysotile open-pit mine in Thetford Mines (Quebec) near the new Road 112. Deterministic and probabilistic analyses were conducted using finite element shear strength reduction and limit equilibrium methods to investigate slope stability. The impact of pit infilling and rapid dewatering as well as long- term stability of the slope were investigated. The results of all analyses reveal that the current mining slopes at LAB Chrysotile are within acceptable design criteria limits. Key words: open-pit mining, slope stability, public infrastructure, deterministic and probabilistic analysis, case study. Resume : Au cours des dernieres annees, plusieurs grandes mines a ciel ouvert ont debute a etre exploitees dans la province de Quebec au Canada, et certains des plus grands puits prevus sont situes a proximite d'infrastructures publiques. Historiquement, les grandes mines a ciel ouvert etaient peu nombreuses dans plusieurs regions minieres, notamment l'Abitibi, ou les mines souterraines sont la norme. En tant que partie integrante de l'acceptation sociale d'une exploitation miniere a ciel ouvert, la stabilite des pentes doit etre soigneusement analysee au cours du processus de conception, et la presence d'infrastructures publiques pres des pentes doit etre dument examinee. La province de Quebec n'a pas de lignes directrices precises au sujet de ces considerations de conception. Cet article fournit un apercu de la litterature sur certaines pratiques actuelles concernant la conception des pentes de l'exploitation miniere pres d'une infrastructure publique. Afin de demontrer son applicabilite dans le contexte de la province de Quebec, l'article presente une analyse de la stabilite du mur ouest de la mine a ciel ouvert LAB Chrysotile, a Thetford Mines (Quebec), pres de la nouvelle route 112. Des analyses deterministes et probabilistes ont ete menees a l'aide des methodes de la reduction de la resistance au cisaillement par elements finis et de l'equilibre limite pour evaluer la stabilite des pentes. L'impact de l'assechement rapide et de remplissage de la fosse, ainsi qu'une stabilite a long terme de la pente ont egalement ete etudies. Les resultats de toutes les analyses revelent que les pentes de l'exploitation miniere actuelle de LAB Chrysotile sont acceptables dans les limites des criteres de conception. [Traduit par la Redaction] Mots-cles: l'exploitation miniere a ciel ouvert, stabilite de pente, infrastructures publiques, analyse deterministe et probabiliste, etude de cas., 1. Introduction Routine stability analysis of open-pit mine slopes involves a trade-off between stability and profit maximization. As the slope angle becomes steeper, the stripping ratio (waste to ore ratio) [...]

A marine environment presents various settings where talus slopes are formed via gravity-driven rockfall processes similar to those existing on land. This is the case along fjords or submarine canyons, where submarine installations or natural sanctuaries, such as coral reefs, need to be protected. In submarine rockfall analysis, the effect of the ambient fluid, in addition to hydrodynamic constraints and water currents, must be considered. A finite volume model has been developed to model two-dimensional rockfall behaviour in a Newtonian fluid, such as water or air. Turbulent and incompressible flow around the moving rock is described with a pressure-velocity iterative method on a dynamic three-dimensional unstructured mesh of polyhedral cells. Pressure, shear, and turbulent forces are then applied to the moving rock. In this paper, we compare underwater rockfall behaviour with air rockfall behaviour in three different situations: free fall, bouncing on a horizontal plane, and bouncing on an inclined plane. A true-scale experiment has been conducted to validate the model. The results of various modeling suggest that, contrary to the air case, the speed of the blocks will be strongly influenced by the block density and volume. Key words: rockfalls, submarine landslides, Navier-Stokes equations, numerical modeling. Tout comme le milieu aerien, le milieu marin peut presenter des environnements ou des talus rocheux sont formeis suite a des processus gravitaires impliquant des chutes de blocs. C'est le cas, par exemple, le long de fjords ou de canyons sous-marins. Un modele numerique a ete deiveloppei afin de modeliser le comportement en deux dimensions des chutes de blocs dans un liquide Newtonien. L'ecoulement incompressible et turbulent du fluide autour du bloc est r solu avec une methode iterative couplant la pression et la vitesse, sur un maillage dynamique non-structure; en trois dimensions compose de polyedres. Les forces dues a la pression, au cisaillement ainsi qu'a la turbulence sont calcukees autour du bloc et ensuite appliqueees a ce bloc afin de definir son mouvement. Dans cet article, le comportement des chutes de blocs dans l'eau sera compare a celui en milieu aerien dans trois situations diffeerentes : la chute libre, le rebond sur une surface horizontale ainsi que le rebond sur une surface inclineie. Un essai grandeur reel a ete realise afin de valider le modele deeveloppe. Les reesultats des diffeerentes modelisations suggerent que la vitesse des blocs sera fortement influenceee par sa masse volumique ainsi que par son volume. Mots-cles: chute de blocs, glissement de terrain sous-marin, equations de Navier-Stokes, modelisation numerique., Introduction The subaerial kinematics of falling rocks has been studied analytically and experimentally for several decades (Ritchie 1963; Pfeiffer and Bowen 1989; Azzoni et al. 1995). Almost all of these [...]

Introduction In their discussion about aerial laser scanning (ALS) and terrestrial laser scanning (TLS), Olsen and Stuedlein present some issues than we did not address in our paper (Jaboyedoff et [...]

For more than 10 years, digital elevation models (DEM) produced by light detection and ranging (LIDAR) technology have provided new tools for geomorphologic studies and especially for landslide studies. In particular, terrestrial laser scanning (TLS) provides a great versatility of use. TLS can be used either for monitoring purposes or in an emergency situation that necessitates a rapid DEM acquisition for assessing a hazard. Using three examples we demonstrate the use fulness of TLS for landslide volume quantification, profile creation, and time series analysis. These case studies are landslides located in sensitive clays of eastern Canada (Quebec, Canada) or small rotational slides in river banks (Switzerland). Key words: aerial and terrestrial laser scanning, landslide, digital elevation models (DEM), sensitive clays, rotational slide. Depuis plus de 10 ans les modeles numeriques d'altitude (MNA) produits par technologie de << light detection and ranging >> (<< LIDAR >>) ont fourni de nouveaux outils tres utiles pour des etudes geomorphologiques, particulierement dans le cas des glissements de terrain. Le balayage laser terrestre (<< TLS >>) permet une utilisation tres souple. Le TLS peut etre employe pour la surveillance ou dans des situations d'urgence qui necessitent une acquisition rapide d'un MNA afin d'evaluer l'alea. Au travers de trois exemples, nous demontrons l'utilite du TLS pour la quantification de volumes de glissements de terrain, la creation de profils et l'analyse de series temporelles. Ces etudes de cas sont des glissements de terrain situes dans les argiles sensibles de l'est du Canada (Quebec, Canada) ou de petits glissements rotationnels dans les berges d'une riviere (Suisse). Mots-cles : balayage laser aerien et terrestre, glissement de terrain, modeles numeriques d'altitude (MNA), argiles sensibles, rotationel slide., Introduction Since the mid 1990s, light detection and ranging (LIDAR) techniques have been extensively used for topographic surveys in various regions. Data acquisition was first performed by airborne laser scanning [...]

Estimates of submarine channel discharges have been combined with an existing data set of measured fluvial discharges to produce generalized bankfull hydraulic geometry relationships. Previous analysis implies that generalized hydraulic geometry relationships are universal across channels formed under a range of gravity conditions. Here we use data from two different subaqueous channel systems formed by flows with distinct buoyancy characteristics to test whether generalized hydraulic geometry relationships apply in reduced gravity environments where channels tend to have relatively steep slopes. On this basis and assuming formative (bankfull) conditions, we derive estimates of Martian paleodischarges and provide better constrained estimates of Martian paleochannel slopes and flow depths, direct measurements of which are otherwise elusive due to structural deformation and erosion since formation. The steeper slopes in reduced gravity environments tend toward greater Froude numbers at formative discharge conditions; this has implications for bedform dynamics and preservation. [ABSTRACT FROM AUTHOR]