Effect of scour remediation by solidified soil on lateral response of monopile supporting offshore wind turbines using numerical model

Abstract

Offshore wind turbines supported by monopiles are inevitably influenced by scour, which will weaken the support provided by soils around and reduce the lateral capacity of the foundations, potentially leading to structure failures. In response, solidified soil is recognized as a promising solution for scour remediation, not only effectively filling the scour holes but also increasing the overall bearing capacity of the monopile. Nevertheless, the mechanism for scour remediation of solidified soil to increase the bearing capacity of the monopile is still unclear. Therefore, this paper mainly investigates the impact of solidified soil on the lateral bearing capacity of monopiles under various scour conditions and compares the effectiveness of different scour remediation methods (i.e., inverted conical remediation to half or all of scour hole and cylindrical remediation to half or all of scour hole). Firstly, the effect of solidified soil on lateral responses of monopile was investigated numerically. The overall load-displacement behavior, profile of bending moment and deflection versus depth of monopile under different scour stages and scour remediation conditions have been fully studied, in addition to the displacement field and failure mode of soil around monopile. It was found that solidified soil can greatly improve the lateral capacity and initial stiffness of monopile, and the cylindrical remediation to all of scour hole scenario showing the greatest improvement. After remediated by solidified soil, the resistance of soil around the monopile is greatly improved, and the rotation center position of monopile is moved up. Furthermore, a series of supplementary sensitivity analyses were conducted to study the effects of remediation parameters (i.e., elastic modulus and strength of solidified soil) and original soil parameter on lateral capacity of monopile.