MPM simulation for the installation of suction caisson as a foundation for offshore wind turbine in sand
Keywords: Offshore, Suction Caisson, Soil-Structure Interaction, Sand
Abstract: Suction caissons have been considered alternative foundations for offshore wind turbines due to their easy installation and cost-effectiveness compared to conventional foundations. It is an open-ended cylindrical steel structure equipped with a lid. After being lowered down by a crane to the seabed, it penetrates the soil by its self-weight; when no further penetration is noticed, suction is applied until it reaches the desired depth. The suction process creates a pressure difference between the inside and outside of the caisson, which acts as an additional downward force. It also induces seepage that degrades the tip resistance and wall friction, further facilitating the installation process. Although seepage plays a vital role in the installation process in the sand, it might change the soil state, affecting the foundation bearing capacity. Taking advantage of MPM as a particle-based numerical method, a large deformation model has been developed to simulate the suction caisson installation. The model takes into consideration the soil-structure interaction by adopting a contact algorithm. This is the first stage of this work, where the sand is modelled as dry material, and the caisson is pushed into the sand (jack installation). This step was important to eliminate numerical instability and error, such as interpenetration and flying points. Next, a two-phase fully coupled model will be developed by applying suction (suction Installation). The model will capture the installation process accurately and investigate the installation safety against undesirable conditions such as plug heave, change of soil state, and piping channel formation.
Submission Number: 14
Loading