Response of an Installed Suction Caisson Induced by Rectangular Footing Penetration in Nonhomogeneous Clay

Abstract

During the construction of an offshore wind turbine (OWT) system, the lifting of the wind turbine blade requires setting up of jacks near preinstalled foundations, which could impact the existing adjacent foundations. To explore the movement characteristics of preinstalled caissons induced by the installation of rectangular footings, this study performs large deformation numerical analyses to quantify these influences. A numerical model is generated and validated against existing testing data in terms of penetration resistance of rectangular footings and soil deformation around the structure. An extensive parametric study is then conducted to quantify the influences of caisson aspect ratio, vertical distance between caisson and two rectangular footings, spacing between two rectangular footings, soil strength, the rectangular footing area, and roughness. It is found that the normalized distance between the caisson and the rectangular footing as well as the caisson aspect ratio play important roles in the movement of the adjacent caisson, with rotational angles of 0.05–0.9°, while the rest factors have limited impacts. Based on numerical results, empirical design formulae are proposed for estimating the maximum inclination angle of the caisson which can be used for engineering application.