Application of convected particle domain interpolation method (CPDI) for predicting dynamic installation processes of offshore monopiles by vibration and impact driving

The global transition to clean energy has been significantly supported by the steady increase in installed offshore wind capacity. Offshore wind energy generation is playing a critical role in this shift, with foundations serving as essential components for these installations. Traditionally, monopiles have been driven into the seabed using impact-driven methods. However, more advanced installation techniques, such as vibratory installation, are gaining popularity due to their faster installation times, reduced underwater noise during the process as well as lower fatigue impact on the steel tube. Despite its advantages, a deeper understanding of the factors influencing the vibratory installation method remains necessary. Numerical tools offer a promising approach for investigating these installation characteristics. In this work, the Convected Particle Domain Interpolation (CPDI) method, an advanced Material Point Method, is utilized for a full dynamic simulation of installation processes incorporating a two-phase extension for the saturated soils. To capture the subsoil characteristicswith greater accuracy, a multi-layered soil continuum is modelled, with results collected at the installation site. The in-house code used in this study has been validated against full-scale monopile installations. Results from the vibratory and impact driving installation of full-scale monopiles at the 'KASKASI-II' wind farm in the North Sea are presented. In addition to analyzing the installation characteristics, the effects of installation frequency and hook-load on the process are explained. The propagation of pressure waves through the seawater generated by the offshore structure during installation are compared to measured field data. For this simulation the model was extended by a model for free water interacting with both the monopile and the saturated soil beneath seabed. This study provides valuable insights into the vibratory and impact driving installation process, offering a comprehensive understanding of the installation dynamics and hydrodynamic effects in offshore wind energy projects.