Suitability of a Pile Group Foundation for an Offshore Wind Turbine

摘要

Monopile, tripod and jacket structures are the most popular foundationsrnadopted in offshore wind farms in Europe. Piles with diameters mostlyrnlarger than 2 m are usually installed for these foundations. More thanrn500 offshore wind turbines shall be installed in the Taiwan Strait in thernnext 20 years. However, due to limited pile driving capacity of thernmarine engineering industry in Taiwan, the pile group foundation withrnpile diameters of maximum D = 1.6 m is considered as foundation forrnoffshore wind turbines and a research platform. This paper aims torninvestigate the behavior of multi-pile-soil system under monotonicrnlateral load. A three-dimensional finite element model with non-linearrnmaterial behavior of the subsoil was established. The deformationrnresponses of a pile group platform foundation calculated with FEMrnunder monotonic lateral load are compared with the results calculatedrnwith a simplified approach based on the p-y-curves method. Thernbearing behavior of the pile group platform foundation cannotrnadequately considered by the simplified approach. To evaluate thernsuitability of group pile platform foundation, the deformation responsesrnof a typical monopile are considered as reference values. Therninvestigated pile group foundation is more flexible than the monopile,rni.e. the lateral deformations of the piles are much larger than therndeformation of the monopile. However, due to the great stiffness of thernplatform plate the rotation of the platform is within the usual tolerancernfor offshore wind turbines and even smaller than the inclination ofrnmonopile.