Installation Constraints of Suction Assisted Foundations and Anchors for Offshore Energy Development

Abstract

The application of suction caissons has increased over the last two decades for offshore energy developments. Their installation challenges in different seabed types affect their execution process and load-bearing capacity. Hence, the identification of these challenges and understanding their root causes are highly important. As such, this paper aims to review the recorded installation constraints due to different seabed conditions, discuss the various factors related to each of these constraints, and finally provide some suggestions to rectify each constraint and/or its relevant factors. To do so, the approach is to evaluate the geological (geophysical and geotechnical) conditions in multiple case studies and analyze the stability of suction caisson installation in different soil types. Results show that some factors such as plug heave contributes about 29% of the installation issues in both homogeneous clay soils and layered clay soils, soil piping and bottom resistance failure contribute about 16% and 10% respectively of the installation issues in both sand and layered sand soils, while high penetration resistance contributes about 23% of installation issues in layered soils. Also, the uncertainty of soil parameters or behavior is a complementary factor which adds more complexities to the above-mentioned factors. Therefore, a good understanding of the seabed conditions and soil parameters before and during installation, as well as constant monitoring of the inducedsuction created during penetration with respect to the penetration depth is essential to mitigate the likely issues.