Pile Installation using MPM

Cause

The growing demand of renewable energy is nowadays satisfied in the offshore industry by designing and building wind farms. To move towards windier areas with a deeper seabed, larger and longer open-ended piles are progressively designed.

Currently, monopiles support about 80% of all offshore wind turbines in Europe and are expected to remain a very popular foundation solution in the coming decade. The design of monopiles does not only depend on the characteristics of the wind turbine, but also on soil conditions, installation technique and severity of repeated (‘cyclic’) loading from wind and waves. Current design practice relies on large safety margins, which results in using more steel than strictly needed. Because support structures make up around 20% of the total investments, optimisation of monopile design can certainly lead to significant cost reduction.

Objective

The knowledge of the installation effects of such large monopiles (larger than 7m diameter) is very limited, due to scarcity of pilot tests, which are also extremely expensive to be performed. There is the need of a reliable and robust tool to assess the response of such large monopiles, including the installation phase, and consequently to improve the design.

TKI PIM aims at gaining insight into the drivability and installation effects of piles subjected to different installation methods (mainly focusing on impact and Blue-piling technology), addressing the role of pore pressure build up induced by the high rate of loading.

Short description

The existing numerical tool of Deltares for pile installation (Material Point Method, MPM) will be improved and validated by means of a set of well-characterized experimental data, which range from 1-g lab- to Ng-centrifuge tests.