Research On Dynamic Response Of Steel Tube Pile Under The Action Of Wave And Current

In recent fifty years, steel tube pile has became an important type of pile in foundation engineering. Steel tube pile is widely used in the deep-water wharf, construction of trestle bridge and the ocean platform. The vertical and horizontal bearing capacity of steel tube pile is relatively high, often as a foundation pile of high, large, heavy structure and the structure of the horizontal force. With the rapid development of the Marine development, Marine oil engineering career, the response characteristics of steel tube pile has gained more and more attention.In port engineering and ocean engineering, Steel tube pile construction in place will be the role of wave and current loads, The dynamic response of steel tube pile under the wave and current loads have an important effects on the structure safety. Especially in the upper part of the structure is not complete, the pile only can rely on their own structures under the loads. In the condition of construction, steel tube pile is in the shape of the single pile, and at this point it is more dangerous, so it is more important to analysis the deformation and stress of steel tube pile in condition of wave and current loads.Firstly, based on the finite element method, this paper establishes a numerical model to calculate the dynamic response of structure. Using eight node hexahedron to mesh, combined with the improved square root algorithm, by solving the node equilibrium equation with unknown node displacement, to get the node displacement and stress of structure. And the Newmark method is used for analysising the dynamic response of structure, to get the structure deformation and stress with the external loads in the schedule change of time domain. Then, using the improved JONSWAP spectrum to simulate the irregular wave spectrum, through the comparison and analysis with the target spectrum inosculation, obtained the simulation parameters of the best simulation effect. And according to the Airy wave theory calculated the velocity and acceleration of the water point at any time point, thus by Morrison formula to calculate the wave and current loads changing over time. Finally, the numerical model is used to the pier steel tube pile in the construction state, and analysised the dynamic response with wave and current loads, obtained the deformation and stress of steel tube pile in the schedule change, and steel tube pile suffered cyclical impact. So using FFT transform on the schedule change curve, through the spectrum analysis, obtained the cyclical impact is mainly caused by the resonance of wave load.