Inventory of Large Landslides in Sensitive Clay in the Province of Québec, Canada: Preliminary Analysis

Demers, Denis; Robitaille, Denis; Locat, Pascal; Potvin, Janelle

doi:10.1007/978-94-007-7079-9_7

Cited by 38 publications

(36 citation statements)

References 7 publications

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“…2). Horsts and grabens observed on this site are typical of spreads occurring in sensitive clays according to Cruden and Varnes (1996), Locat et al (2011), and Demers et al (2013).…”

Section: Introductionmentioning

confidence: 63%

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The 1994 landslide at Sainte-Monique, Quebec: geotechnical investigation and application of progressive failure analysis

et al. 2015

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Abstract:In 1994, a landslide occurred in the municipality of Sainte-Monique, Quebec. The debris of the landslide had graben and host shapes, typical of spreads in sensitive clays. The geotechnical investigation shows that the soil involved is a firm to stiff, sensitive, nearly normally consolidated grey silty clay of high plasticity. This soil exhibits a high sensitivity and a high brittleness during shear and is therefore susceptible to progressive failure. Traditional stability analysis cannot explain this landslide. This gives the opportunity to examine the applicability of progressive failure analysis to this spread. Using the finite elements method, it is demonstrated that the initiation and observed extent of the failure surface are explained by a soil having high brittleness during shear and a large-deformation shear strength close to the remoulded shear strength of the soil. The dislocation of the soil mass can also be explained by the active failure occurring in the soil mass above the failure surface during or shortly after failure propagation. It is therefore numerically demonstrated that progressive failure explains the initiation and the extent of the failure surface of this spread.Key words: progressive failure, spread, sensitive clay, large-deformation shear strength, brittleness.Résumé : Un glissement de terrain est survenu en 1994 dans la municipalité de Sainte-Monique, Québec. Les débris présentaient des formes de horsts et grabens typiques des étalements dans les argiles sensibles. L'investigation géotechnique démontre que le sol impliqué dans ce glissement est une argile silteuse grise normalement consolidée, sensible, de forte plasticité et ayant une consistance ferme à raide. Ce sol présente une sensibilité et une fragilité lors du cisaillement élevées et peut donc être susceptible à la rupture progressive. Les analyses de stabilité traditionnelles n'arrivent pas à expliquer ce glissement. Ceci offre donc l'opportunité d'examiner l'application du concept de la rupture progressive sur cet étalement. À l'aide de programmes d'éléments finis, il est démontré que l'initiation et l'étendue de la surface de rupture observée peuvent être expliquées par un sol ayant une grande fragilité lors du cisaillement et une résistance à grandes déformations près de la résistance du sol remanié. La dislocation de la masse de sol en horsts et grabens est expliquée par la rupture active survenant dans la masse de sol au-dessus de la surface de rupture pendant ou peu après la propagation de la rupture. Il est donc démontré numériquement que la rupture progressive explique l'initiation et l'étendue de la surface de rupture d'un étalement.

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“…2). Horsts and grabens observed on this site are typical of spreads occurring in sensitive clays according to Cruden and Varnes (1996), Locat et al (2011), and Demers et al (2013).…”

Section: Introductionmentioning

confidence: 63%

“…Spreads represent 37% of the large landslides (larger than 1 ha) occurring in the Province of Quebec (Demers et al 2013). They are a great threat to populations and infrastructures located on sensitive clays, as they occur rapidly, without any known warning, and may involve large areas (Demers et al 2013).…”

Section: Introductionmentioning

confidence: 99%

The 1994 landslide at Sainte-Monique, Quebec: geotechnical investigation and application of progressive failure analysis

et al. 2015

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“…Based on initiation and progression of the sliding surfaces or shear bands, the failure of slopes can be divided into two categories, namely upward and downward progressive failures. Upward progressive failure might be initiated by excavation, erosion or small slides in the river bank slopes (Quinn et al, 2007;Locat et al, 2008;Demers et al, 2014). Downward progressive failure could be triggered by vertical loading or pile driving in the upslope area (Bernander, 2000;Gylland et al, 2010).…”

Section: Introductionmentioning

confidence: 97%

Large deformation finite-element modelling of progressive failure leading to spread in sensitive clay slopes

et al. 2015

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The occurrence of large landslides in sensitive clays, such as spreads, can be modelled by progressive development of large inelastic shear deformation zones (shear bands). The main objective of the present study is to perform large deformation finite-element modelling of sensitive clay slopes to simulate progressive failure and dislocation of failed soil mass using the coupled Eulerian Lagrangian (CEL) approach available in Abaqus finite-element software. The degradation of undrained shear strength with plastic shear strain (strain-softening) is implemented in Abaqus CEL, which is then used to simulate the initiation and propagation of shear bands due to river bank erosion. The formation of horsts and grabens and dislocation of soil masses that lead to large-scale landslides are simulated. This finite-element model explains the displacements of different blocks in the failed soil mass and also the remoulding of soil around the shear bands. The main advantages of the present finite-element model over other numerical models available in the literature are that it can simulate the whole process of progressive failure leading to spread. The finite-element results are consistent with previous conceptual models proposed from field observations. The parametric study shows that, depending upon geometry and soil properties, toe erosion could cause three types of shear band formation: (a) only a horizontal shear band without any global failure; (b) global failure of only one block of soil; (c) global failure of multiple blocks of soil in the form of horsts and grabens.

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“…Landslides involving sensitive clays typically occur as spreads or flows (flowslides) depending in part on the degree of remoulding of the displaced material (Demers et al, 2014;Geertsema et al, 2017). Spreads display both extensional ridges and depressions, typically referred to as horsts and grabens, oriented perpendicular to movement direction ( Fig.…”

Section: Introductionmentioning

confidence: 99%

“…Spreads display both extensional ridges and depressions, typically referred to as horsts and grabens, oriented perpendicular to movement direction ( Fig. 1) (Carson, 1977(Carson, , 1979Geertsema, 2004;Geertsema et al, 2006b;Demers et al, 2014Demers et al, , 2017. Spreads often involve movement along and remoulding of thinner sensitive zones.…”

Section: Introductionmentioning

confidence: 99%

Sensitive clay landslide detection and characterization in and around Lakelse Lake, British Columbia, Canada

Geertsema

Blais-Stevens

Kwoll

et al. 2018

Sedimentary Geology

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The Lakelse Lake area in northwestern British Columbia, Canada, has a long history, and prehistory, of rapid sensitive clay landslides moving on very low gradients. However, until now, many landslides have gone undetected. We use an array of modern tools to identify hitherto unknown or poorly known landslide deposits, including acoustic subbottom profiles, multibeam sonar, and LiDAR. The combination of these methods reveals not only landslide deposits, but also geomorphic and sedimentologic structures that give clues about landslide type and mode of emplacement. LiDAR and bathymetric data reveal the areal extent of landslide deposits as well as the orientation of ridges that differentiate between spreading and flowing kinematics. The subbottom profiles show two-dimensional structures of disturbed landslide deposits, including horst and grabens indicative of landslides classified as spreads. A preliminary computer tomography (CT) scan of a sediment core confirms the structures of one subbottom profile. We also use archival data from the Ministry of Transportation and Infrastructure and resident interviews to better characterize historic landslides.

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Inventory of Large Landslides in Sensitive Clay in the Province of Québec, Canada: Preliminary Analysis

Cited by 38 publications

References 7 publications

The 1994 landslide at Sainte-Monique, Quebec: geotechnical investigation and application of progressive failure analysis

The 1994 landslide at Sainte-Monique, Quebec: geotechnical investigation and application of progressive failure analysis

Large deformation finite-element modelling of progressive failure leading to spread in sensitive clay slopes

Sensitive clay landslide detection and characterization in and around Lakelse Lake, British Columbia, Canada

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