Research on sinking and leveling control technology of tripod bucket foundation in sand

Abstract

High capacity wind-turbines are increasingly installed offshore and further away from the coast, where strong foundations are required, and their installation is challenging. The so-called multi-bucket foundation is a promising candidate to be used for such scenarios. However, the sinking control technology, which is commonly used to ease the installation, is not very mature. In this paper, a series of theoretical studies and tests are carried out to investigate the sinking process of a wide-shallow tripod bucket foundation (WTBF). First, the mechanism of seepage-failure of a WTBF at different depths is investigated using both empirical formulas and experiments. In addition, the optimal method to calculate/predict seepage-failure of a WTBF in the sand and the value range of the kfc coefficient are determined. Then, an experiment to determine the maximum adjustable initial tilt-angle (based on seepage failure control) is conducted. This enables the improvement/determination of the control index and control methods for seepage failure as well as the tilt-angle during the sinking process. Finally, an automatic control system for the sinking and leveling of the multi-bucket foundation, which uses a dual-index control method (seepage failure, leveling angle) is developed. The feasibility of this approach is verified through experiments.