The Dynamic Response Of Offshore Jack-up Platform

In this paper we study a offshore jack-up piling platform working in the sea area,and analyze the static strength and nonlinear dynamic response of it on the extreme sea environments with the ANSYS FEM software.On the base of the results we make following discuss of static and dynamic characteristic of jack-up platform.The major contents are summarized as follows:1) A 3D FEM of a offshore jack-up piling platform is established in this paper,and the static strength and nonlinear dynamic response of it on the extreme sea environments are analyzed.The results show that the value of dynamic response of jack-up platform on dynamic load is greater than the static.lt maybe thanks to the flexibility of jack-up platform is great.Thereby we can enduce the conclusion,that the static strength analysis is not enough for the jack-up platform on the extreme sea environments and the dynamic response analysis is necessarily.2) The Winkler beam model is used to simulate pile-soil dynamic interaction.The soil is treated as Winkler foundation.The pile is disposed as beam imbedded in the soil.Then according to geologic information of the working sea area(P-y,t-z,Q-z curve),the nonlinear spring is used to simulate the counterforce of soil .And then compare with the mode of fixed end restraint,the effect of structure-pile-soil mutual interaction is systematically studied.3) Based on the model of structure-pile-soil,the deepth of pitching pile has been studied.The results show that the max displacement is not discreasing with the deepth of pitching pile, on the contrary it will increasing when reach a minimum value.And the value has some practicality in the work.4) Also there are two types of pile shoe has been studied in this paper.The results show that the pile shoe greatly enhance the structural strength of jack-up platform. Furthermore the harmfulness of wave wash are also discussed in this paper and protective measure are brung forward.