Study on Fundamental Force of Extreme Wave on Complex Deepwater Jacket

Abstract

With the development of offshore wind power to the far-reaching sea, jacket foundation suitable for 10 ~ 60m water depth has become a development trend. The maximum waves in the far-reaching sea are generated by typhoons. The South China Sea spans the tropics and subtropics. Tropical cyclones therein are extremely active due to the features of its marine environment, like wide water-depth profile, complex topography and hydrology. Especially in recent years, under the development situation of global warming, extreme weather events have increased significantly, and strong and super typhoons have become more frequent. The extreme waves generated by them have a huge force on the jacket, affecting the safety of the project. In this paper, the relevant parameters of PMTC are calculated with the statistical method, the verified SWAN model is used to calculate the probable maximum typhoon wave, and the P-III frequency analysis on the extrapolated results of all typhoon waves are carried out by direction to obtain the design wave elements of each return period, and various extreme typhoon wave characteristic parameters were counted. Secondly, the Morison formula is used to calculate the wave force acting on the offshore fan jacket. This wave force based on different water depth and different directions is tested by physical model test. Finally, the results of model test and theoretical calculation are compared and analyzed to confirm that there is a certain correlation between the two wave forces. This empirical formula can be used to correct the calculated value of Morison formula in practical engineering design, which not only provides a simple and convenient calculation method for practical engineering design, but also provides a reference for the calculation model of the total force generalization of deep-sea complex structure foundation, which has certain theoretical value and practical significance.