Analyses of Spudcan Penetration and its Effect on an Adjacent Offshore WTG Monopile Foundation

1. Home
2. Publications
3. Online Library
4. Analyses of Spudcan Penetration and its Effect on an Adjacent Offshore WTG Monopile Foundation

This paper presents the numerical evaluations performed to assess the effect of spudcan penetration and extraction adjacent to the monopile foundation (MP) of an offshore WTG. The analyses aimed to estimate changes in stratigraphy, seabed condition, and soil strength due to spudcan installation and extraction, evaluate their impact on monopile lateral capacity, and assess the effectiveness of mitigation measures.

For the assessment of spudcan penetration and extraction and the extent of disturbance, Finite Element analyses were performed. Due to the highly nonlinear nature of the penetration problem, a large deformation formulation was utilized in conjunction with the Coupled Eulerian-Lagrangian (CEL) technique in ABAQUS. The numerical approach adopted was validated against a case-history and a centrifuge test. Significant spudcan penetrations, on the order of 20 meters, were simulated with post-extraction depressions on the order of 2 meters.

For the assessment of the impact of spudcan penetration and extraction on the MP lateral response, 3D pushover analyses were performed with the finite difference code FLAC3D. The numerical analyses were intended to model the nonlinear MP-soil interaction due to the static monotonic application of a load combination at the top of the MP resulting in the development of shear, axial force and bending moment at seafloor level. Analyses results indicated that mitigation measures (filling of the spudcan depression with rock) and the presence of scour protection (which was not considered in the original MP design) provide additional resistance which exceeds the effects of spudcan disturbance.

5th International Symposium on Frontiers in Offshore Geotechnics (ISFOG2025)

14 - Spudcans: penetration, extraction, interactions