Depending on the prevailing bathymetrical and geotechnical conditions, the integrity of offshore pipelines is threatened by potential slope instabilities that occur at the seabed or at the bottom of lakes. In addition, submarine slides are more frequent in seismic regions. The instability of onshore slopes under seismic conditions is undoubtedly a challenging problem in geotechnical earthquake engineering, while the quantitative assessment of the seismic stability of submerged slopes is even more demanding. Consequently, the current study investigates this complex phenomenon of offshore geotechnical earthquake engineering. After a brief overview of the recent related work of the authors’ group and the available pseudo-static methods of the literature, an improved analytical method is proposed. An indicative parametric study demonstrates that the new approach estimates more accurately the factors of safety, leading thus to less conservative (i.e., more cost-effective) design of offshore pipelines near potentially unstable submarine slopes.
National Technical University of Athens