Introduction  As an important construction equipment in the development of offshore wind power, studying the bearing performance of the jack-up vessel for wind turbine installation in the in-situ state to ensure its operation safety is of great significance.

  Method  In this paper, taking the jack-up installation vessel as the research object, the horizontal bearing performance of the jack-up installation vessel and the variation law of the surrounding earth pressure at four different penetration depths of spudcans in homogeneous sandy soil were studied by combining with the indoor model tests and finite element method.

  Result  The results show that with the increasing of the penetration depth, the horizontal bearing capacity of the jack-up installation vessel is on an approximate linear growth trend. The penetration depth of 10 cm led to an increase of the horizontal bearing capacity by 38.02% compared with 4 cm penetration depth, and the corresponding horizontal displacement also show an increasing trend. Under the action of horizontal loads, the bearing mode of spudcans is characterized by compression of spudcans on the loading side and tension of spudcans on the non-loading-side. The pressure change law of the soil on the surface of spudcans is the same. At the penetration depth of 10 cm, the maximum variation in soil pressure at the bottom of spudcans on the loading side is 38.37 kPa, which increased by 126.2% compared to the penetration depth of 4 cm. In addition, significant variations in soil pressure are observed on the lower surface of the loading-side spudcans and the upper surface of the non-loading-side spudcans.

  Conclusion  Under the action of horizontal load, the force mode of the jack-up installation vessel is the tension-compression mode, and increasing the penetration depth of spudcans in sandy soil can significantly enhance the horizontal bearing capacity. Therefore, in order to ensure the safety and operational capability of the wind turbine installation vessel, it is necessary to ensure sufficient penetration depth of spudcans.