Probabilistic Slope Stability Analysis In The West Nile Delta Offshore Egypt

Proceedings of the 7th International Conference 'Integrated Geotechnologies – Present and Future', 12–14 September 2012 at the Royal Geographical Society, London. Offshore Site Investigation and Geotechnics (OSIG) Group of the Society for Underwater Technology (SUT).

12 Sep 2012
P. Dimmock, B. Mackenzie, A. Mills

Abstract:
Probabilistic slope stability analysis has been performed for the West Nile Delta (WND) deepwater area, off-shore Egypt. It has been used to minimise geohazard risk for the WND subsea development. The analysis was premised on earthquakes being the predominant trigger of slope instability, exacerbated in the past by excess pore pressures generated by relatively rapid sediment accumulation. Earthquake-induced slope displacements calculated using the Newmark method were mapped to a pseudostatic safety factor to facilitate area-wide char-acterisation of slope failure probability. The annual probability of slope failure was assessed across the WND development area within ArcGIS, incorporating mapped variable geological controls (e.g. soil strength, slope angle) as inputs. Failure probabilities were spatially generated using the concept of slope facets, defined as areas of seabed with similar expected susceptibility to slope failure, based on geomorphological examination.

 

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