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TitreRegional slope stability assessment: Challenges in spatial and stratigraphic geologic and geotechnical data integration
AuteurMosher, D C; MacKillop, K; Latour, V; Fenton, G; Mitchelmore, P
SourceCommission géologique du Canada, Dossier public 6646, 2010, 1 feuille, (Accès ouvert)
ÉditeurRessources naturelles Canada
Documentdossier public
Mediapapier; en ligne; numérique
Formatspdf; JPEG2000
ProvinceRégion extracotière de l'est
Lat/Long OENS-68.0000 -54.0000 46.0000 41.5000
Lat/Long OENS-56.0833 -54.6667 45.2500 43.5833
Sujetsglissements de pentes; stabilité des pentes; analyses de la stabilité des pentes; bathymétrie; levés sismiques; levés de reflexion sismiques; levés de refraction sismiques; levés sismiques marins; interpretations sismiques; topographie du fond océanique; carottes de sédiment marin; levés géophysiques; affouillement; levés acoustiques; talus continental; glissements de terrain; dépôts de glissement de terrain; géologie marine; géophysique
Illustrationsseismic profiles; location maps; profiles; graphs; plots
Diffusé2010 05 28
Résumé(disponible en anglais seulement)
Recent oil and gas exploration in Eastern Canada includes deep water continental slope regions. Sediment instability and risk of submarine mass failure is the most significant geohazard in this environment, as demonstrated in the rock record and even in historic times with the 1929 Grand Bank's landslide. An abundance of seismic reflection data and numerous piston cores along the Nova Scotia continental margin make it an ideal area to perform a regional slope stability assessment. Site-specific assessments typically involve slope stability analysis to predict static and dynamic critical slope failure conditions. Vertical measurements of sediment geotechnical properties used in these analyses can be reasonably extrapolated on local scales for site assessment purposes. Regional slope stability assessments, however, have the challenge of integrating geological and geotechnical conditions that vary spatially and stratigraphically. In this study, a simplified geostatistical approach was adopted to assess the effect of spatial variability of soil properties on slope stability analysis. Probabilistic and deterministic engineering assessments were performed for both non-spatially averaged and spatially averaged core sections. Results indicate that the estimated factor of safety increased by 30% when spatially averaged values were used. A slope of 10o has a 50% probability of failure under static conditions. The average slope angle for the area is between 1 and 3o. In this case, a seismic coefficient of ~12% is required to initiate instability. Given the abundance of mass transport deposits in the stratigraphic section, occasional strong earthquakes to generate these coefficients must have occurred in the past. Other contributive factors may have resulted in weakening of sediment in the stratigraphic section to lessen these critical coefficients.