Wave‐Induced Slides in South Pass Block 70, Mississippi Delta

TLDR

A major offshore platform failed due to a seafloor slide and hurricane wave forces. The study proposes ultimate‑strength design methods to supplement existing elastic methods for slide‑resistant platforms. The authors combine soil and wave data with limit‑equilibrium, finite‑element, and layered‑continuum models to assess soil movements and forces. The analysis estimates the platform foundation’s ultimate strength and finds good agreement between force and resistance characterizations.

Abstract

Failure of a major offshore platform caused by a seafloor slide and hurricane wave forces is described. Data on the soils and waves are combined with limit equilibrium, finite element and layered continuum analytical models to determine soil movements and forces. Estimates are made of the ultimate strength of the platform foundation. Comparison of force and resistance characterizations indicates good agreement. Ultimate strength design methods are suggested to supplement present elastic methods in design of slide‐resistant platforms.