Research On Dynamic Response Of All Vertical High Piled Wharf In Deep Water

With the vigorous development of China's water transportation and the need for large-scale seaport construction,offshore all vertical high piled wharves in deep water have become the trend of future port construction in China.Different from the traditional high-piles wharf,all vertical high piled wharves in deep water are generally built on offshore soft-soil foundations,and are mainly subjected to cyclic dynamic load caused by waves.The waves are often accompanied by ocean currents in its propagation,Wave-current interactions will change the wave elements.The interaction mechanism of wave-current-pile-soil-wharf structural system is more complex.In this paper,the Doppler effect of wave-current interaction is theoretically discussed.Based on the characteristic wave method and spectral analysis method,the calculation method of wave current load is studied.Taking an all vertical high piled wharf project as a prototype,a deterministic response model and a stochastic response model for all vertical high piled wharf under wave current loading are established by numerical simulation,The theory and calculation method of the wave-current-pile-soil-wharf structure system are studied to solve the problem of deformation and vibration stability of the all vertical high piled wharf under wave-current loads,which will provide the theroretical support for the construction of offshore engineering in deepwater.(1)Based on the non-linear Winkler beam method,P-Y curves considering soil strength degradation under cyclic loading are used to simulate pile-soil interaction.A finite element simulation model of the all vertical high piled wharf structure is established by joint programming of matlab and APDL.(2)Based on the Morison equation,the wave load is calculated by using the characteristic wave method and the spectrum analysis method.The variation law of the wave load with the wave height and period is studied.The Doppler effect of the wave-current interaction is analyzed.Based on wave flux conservation theory,the variation of wave elements under the interaction of wave currents is analyzed.The wave spectrum deformation law and the influence of ocean currents on wave loading are discussed.It has been found that the forward current will cause the wave height to decrease and the wavelength to become longer,that is,the wave steepness becomes smaller and the wave shape is more gentle;the current will greatly increase the drag force acting on the pile and increase the total wave load.(3)Combining the characteristic significant wave method and the spectrum analysis method,the time history response and random vibration law of the all vertical high piled wharf structure under the action of wave current laod are studied respectively.Based on the characteristic significant wave method,the effect of wave height,periods and current on the structural response is studied.Based on the spectral analysis method,the stochastic response calculation model of the linear system is established and the 1?(standard deviation)solution and response spectral density curves of the structural response are obtained.It is found that the structural response is the most sensitive to the change of wave height and does not show significant correlation with the wave period.The wave-current interaction will increase the structural response.