Effect of single and dual voids on lateral capacity of large-diameter monopiles in marine clay

Abstract

This study numerically examines the effect of single and dual voids on the lateral bearing capacity of nearshore large-diameter monopiles in marine clay by the finite element limit analysis (FELA) method. The ability of the numerical model to accurately predict the pile-void system behavior is evaluated by performing degenerated verification analyses on existing studies. Based on numerous numerical results, several design charts for capacity reduction coefficients are produced to provide a quick and straightforward assessment of the pile capacity with single and dual voids by multiplying that without voids by coefficients. Particularly, the coupling coefficient is further proposed to quantify the coupling effect between dual voids, and the corresponding design charts are also given. The subsequent parametric studies indicate that the void effect gets aggravated as the void is enlarged and close to piles but would be weakened as the soil around the pile gets strengthened; the void effect is positively and negatively associated with the void depth in the cases of low and great shear strength, respectively. The effect of single and dual voids (inc. coupling effect between dual voids) on the pile capacity and failure mode is further graphically explained by the plastic multiplier contour maps.

Keywords:

• Large-diameter monopile
• lateral bearing capacity
• void
• marine clay
• reduction coefficient
• finite element limit analysis

Acknowledgments

The authors are thankful to OptumCE for the free access of OptumG2 program (academic edition) to perform this study.

Data availability statement

Some or all data, models, or codes that support the findings of this study are available from the corresponding author upon reasonable request (the data in the graph and the code of calculation, etc).

Disclosure statement

No conflict of interest exists in the submission of this manuscript, and the manuscript is approved by all authors for publication.

Additional information

Funding

This research is part of work supported by grants from the Hunan Provincial Natural Science Foundation of China (No. 2022JJ40074) and the National Natural Science Foundation of China (No. 52108317).