Method to determine the ultimate horizontal bearing capacity of offshore wind turbine monopiles with grouting protection against scouring

Scouring is a serious occurrence that jeopardises the securing of offshore wind power structures. This research investigated the effectiveness of grouting protection as a novel countermeasure to scouring. In order to accomplish this objective, scouring experiments were conducted under constant-current and regular-wave. Furthermore, static loading tests of the monopile were carried out. The results indicate that the ultimate scouring depths of piles with grouting were significantly lesser than those without it during scouring. Additionally, it was observed that grouting protection can considerably enhance the ultimate horizontal bearing capacity under static loading. The limit equilibrium method was employed to determine the ultimate horizontal bearing capacity of monopiles. Two models were proposed for piles with grouting protection––the pile-reinforced sediment model (Model A) and the composite pile model (Model B). We determined that Model An underestimated the ultimate horizontal bearing capacity, whereas Model B overestimated it. Therefore, coefficients for these calculations were acquired to ensure the accuracy of the results. These findings could help in reducing the costs of operating and maintaining offshore wind farms while offering an enhanced design for scouring protection in offshore wind power foundations. •Apply grouting to scouring protection.•Demonstrate the effect of grouting protection on scour.•Employ limit equilibrium method to determine the ultimate horizontal bearing capacity.•Proposed pile–reinforced sediment model and composite pile model.