Regional slope stability and slope-failure mechanics from the two-dimensional state of stress in an infinite slope

Mello, Ulisses T.; Pratson, Lincoln F.

doi:10.1016/s0025-3227(98)00122-4

Cited by 33 publications

(16 citation statements)

References 7 publications

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“…Over the last two decades, the submarine slope failures were intensely investigated because of the assessing of the seabed stability, the deep-water material transportation and the exploration and exploitation of hydrocarbon resources in the deep sea (Campbell, 1999;McAdoo et al, 2000;Gee et al, 2001;Masson et al, 2002;Canals et al, 2004;Evans et al, 2005;Vanneste et al, 2006;Ercilla et al, 2008;Gong et al, 2014;Alfaro and Holz, 2014). And the main triggering agents or mechanisms for the submarine slope failure were summarized as earthquakes, tsunamis, decomposition of gas hydrates, overpressure, fluid flow and sedimentary instability (Bugge et al, 1987;Mello and Pratson, 1999;Dugan and Flemings, 2000;Bünz et al, 2003Bünz et al, , 2005Canals et al, 2004;Evans et al, 2005;Mienert et al, 2005;Greene et al, 2006;Brown et al, 2006;Gee et al, 2006Gee et al, , 2007Vanneste et al, 2006;Paull et al, 2008;Lopez et al, 2010).…”

Section: The Relationship Among the Focused Fluid The Slope Failure mentioning

confidence: 99%

Architecture, evolution history and controlling factors of the Baiyun submarine canyon system from the middle Miocene to Quaternary in the Pearl River Mouth Basin, northern South China Sea

Zhou

Wang

Gao

et al. 2015

Marine and Petroleum Geology

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Section: The Relationship Among the Focused Fluid The Slope Failure mentioning

confidence: 99%

Architecture, evolution history and controlling factors of the Baiyun submarine canyon system from the middle Miocene to Quaternary in the Pearl River Mouth Basin, northern South China Sea

Zhou

Wang

Gao

et al. 2015

Marine and Petroleum Geology

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“…Moreover, it is likely that the survey was performed just after the slump because, in this area, wave action is likely to re-establish quickly some kind of equilibrium profile. The causes of this type of slump on the delta front could be the angle of sediment repose, or external forcing due to sediment load arising from mouthbar accretion and changes in pore pressure due to wave conditions (Nemec, 1990;Mello and Pratson, 1999;Hill and Christian, 2003). However, it is not known if flood events directly induce these sorts of sediment slides, since this observed slump exists on the pre-flood morphology.…”

Section: Delta Frontmentioning

confidence: 99%

Morphological changes and sedimentary processes induced by the December 2003 flood event at the present mouth of the Grand Rhône River (southern France)

et al. 2006

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The study, which is based on repetitive bathymetric surveys, assesses changes and effects of one of the most important floods recorded in the Rhône Delta area: bottom morphology and sediment distribution in the Rhône outlet after the December 2003 flood are discussed by comparison between Digital Terrain maps (DTMs) of November 2003 and January 2004.The post-flood morphology shows that the whole of the system is active, mainly in the east. The channel of the Rhône has been hollowed out on the left bank by more than 5 m, the eastern coast of the mouth has retreated 400 m, the mouth-bar has prograded 200 m and the slope of the delta front has increased by 0.19°. The overlay of pre-and post-flood DTMs makes it possible to estimate the total volume deposited in the [0 to −20 m] zone as +7.8 × 10 6 m 3 (i.e. 0.88 m 3 m − 2 ), which corresponds to 4 × 10 6 t of sediment. These values are compared with the average annual volume of 0.47 × 10 6 m 3 yr − 1 of sediment deposited in this zone between 1995 and 2003, as well as the average sediment load estimated at the Arles station (50 km upstream) for this flood event (3.1 × 10 6 t to 5.3 × 10 6 t).The acquisition of bathymetric measurements immediately before and after a major flood allows more than a simple morphological description; in addition, an analysis of the solid load transfer processes towards the prodelta is achievable. Three mechanisms are highlighted. Most of the material eroded in the channel and supplied to the delta front corresponds to fine sediment that drape homogeneously over the pre-flood morphology of the delta front. The transit of the coarsest sediment (primarily sand) is slowed down in the channel of the Rhône: this sediment builds up in relatively small areas, leading to the formation of gullies on the prodelta slope. The gullies have fixed positions and disappear gradually towards the west, following the progressive migration of the active band towards the east. These old features are not reactivated by floods occurring after their formation. During the flood, only a small volume of coarse sediment bypasses through the gullies, and the fine deposits are remobilised rapidly or compacted. Flood input concerns essentially the delta front, which traps 90% of the fluvial solid discharge between 0 and 20 m depth. The coarse prodelta supply is then due mainly to mass movements of unconsolidated material deposited beforehand on the top of the delta front. Consequently, the main nourishment of the prodelta does not occur directly during and/or immediately after a flood event, but is delayed by sediment being temporarily trapped on the delta front.

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“…While some of the researchers used computer programs, such as Slope/W, to accommodate complex geometry and soil profiles, a large number of studies simply assumed infinite slope conditions (Almagor and Wiseman 1991;Mello and Pratson 1999;Dimakis et al 2000;Leynaud et al 2004;Kvalstad et al 2005b;Nixon and Grozic 2007). One of the major limitations of the limit equilibrium method is that it cannot explain the progressive development of a failure surface due to post-peak softening of sensitive clays.…”

Section: Introductionmentioning

confidence: 99%

Modeling of large-deformation behaviour of marine sensitive clays and its application to submarine slope stability analysis

et al. 2016

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Post-slide investigations suggest that many large-scale submarine landslides occur through marine sensitive clay layers. A nonlinear mathematical model for post-peak degradation of undrained shear strength of sensitive clay is proposed based on experimental results. A method for estimation of model parameters is presented. Incorporating the model, an analytical solution is developed to examine possible mechanisms of large-scale submarine landslides. Analyses are performed for mild infinite slopes where the failure initiates from a "fully weakened zone" of soil having undrained shear strength lower than the shear stress acting parallel to the slope. The driving force, in excess of resistance, generated from the fully weakened zone is then transferred to the surrounding soil elements resulting in shear band formation due to strain-softening behaviour of sensitive clays. When the length of the fully weakened zone is greater than a critical length, catastrophic shear band propagation (self-driven without any additional external force) occurs, which could result in large-scale offshore landslides. A simple design chart is developed to calculate the critical length. Compared with a 2005 study by Puzrin and Germanovich based on a linear post-peak shear strength degradation model, the present study gives a conservative estimation of critical length for catastrophic shear band propagation.Key words: sensitive clay, large deformation, submarine landslides, shear band, undrained shear strength.Résumé : Les enquêtes post-glissement de terrain suggèrent que de nombreux glissements de terrain sous-marin à grande échelle se produisent à travers les couches d'argiles marines sensibles. Un modèle mathématique non linéaire de la dégradation post-pic de la résistance au cisaillement non drainée de l'argile sensible est proposé sur la base de résultats expérimentaux. Une méthode d'estimation de paramètres du modèle est présentée. Incorporant le modèle, une solution analytique est développée pour examiner les mécanismes possibles de glissements de terrain sous-marin à grande échelle. Les analyses sont effectuées pour des pentes infinies douces où l'échec est entamé à partir d'une « zone totalement affaiblie » du sol ayant une résistance au cisaillement non drainé inférieure à la contrainte de cisaillement agissant parallèlement à la pente. La force d'entraînement, au-delà de la résistance, générée à partir de la zone entièrement affaiblie est transférée aux éléments de sol environnant aboutissant en la formation de bandes de cisaillement en raison du comportement d'adoucissement à la déformation des argiles sensibles. Lorsque la longueur de la zone entièrement affaiblie est supérieure à une longueur critique, une propagation d'une bande de cisaillement catastrophique (auto-conduit sans aucune force externe supplémentaire) se produit qui pourrait entraîner des glissements de terrain en mer à grande échelle. Un graphique de conception simple est développé pour calculer la longueur critique. Par rapport à une étude réalisée e...

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Regional slope stability and slope-failure mechanics from the two-dimensional state of stress in an infinite slope

Cited by 33 publications

References 7 publications

Architecture, evolution history and controlling factors of the Baiyun submarine canyon system from the middle Miocene to Quaternary in the Pearl River Mouth Basin, northern South China Sea

Architecture, evolution history and controlling factors of the Baiyun submarine canyon system from the middle Miocene to Quaternary in the Pearl River Mouth Basin, northern South China Sea

Morphological changes and sedimentary processes induced by the December 2003 flood event at the present mouth of the Grand Rhône River (southern France)

Modeling of large-deformation behaviour of marine sensitive clays and its application to submarine slope stability analysis

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