Dynamic Response Of Row-Piles To The Force Of Wave And Bore

With the development of ocean techniques, more and more ocean constructions, such as high pile dock, ocean flat, span ocean bridge, are built. Pile foundation is the most popular foundation. The coupling vibration of "liquid-pile group-soil" has been the key problem, recently. In addition, the pile groins are the new type constructions, which were first used in Qiantangjiagn River. The strength mechanism is similar to ocean flat, high pile dock. It's urgent to solve the dynamic response to direct the project design.First, based on the Biot Concretion Theory and the uniform poro-elastic medium model, the dynamic response of the riverbed is deduced. The soil sketeton displacement is obtained, considered the effects of parameters of the waves and the soils, the module's change due to the waves is studied, and this work provides dependable reference to the calculation of coupling vibration of "liquid-pile group-soil".For the large scale embedded pile.Based on the velocity potential eigenfunction expansion, the pile and the soil are assumed as elastomer and winkler foundation, the condition that the stress and the displacement of the pile are continuous on the soil surface establishes the equations, which figure that the pile couplers the liquid, or the lateral velocity of the pile equals the lateral velocity of the liquid on the pile surface, the analytical resolution of the embedded pile's vibration in non-viscous liquid is found. The study indicates that the non-viscous liquid's acting force on the elastic pile differ the force on the rigid pile greatly, especially when the pile stiffness and the soil mudule are small. When the frequency of the incident wave approaches the natural vibration frequency, the swing of the pile reaches peak, while the acting force is relatively less.For the small scale embedded pile, the wave force that acts on the small scale pile adopts the modified Morison Equation. The pile-soil element model and the pile-water element model are established, by the numerical method, the dynamic response of pile to the wave load is calculated. Then this mumerical method is compared with the traditional 6-diameter method and the method that ignores the couple of water and pile.For the small scale embedded pile group, the wave force is calculated with criterion standard, and pile group effect is considered when the pile-soil interaction is analysed. The numeration result indicates that the strength mechanism of embedded pile group is very complex, the dynamic resoponse is relative to the factors,such as incidence angle, space between piles, and the arrange mode of piles. The method in this thesis considers the pile-water couple and the effect that the embedded soil on the pile, so the dynamic response is factually simulated.The dynamic response of the piling groins under the tidal bore in Qiantangjiang River is the special instance of the "pile-soil-liquid" coupling vibration problem. The tidal bore has high tide, large velocity of liquid and strong wallop, the new type hydraulic system's dynamic response emphases the particularity of the tidal bore of the Qiantangjiang River. The tidal bore pressure's history and the distribution is obtained by locate testing and numerical simulation, based on the research about the embedded pile's coupling the liquid. The measured Qiantangjiang River bore loading is presented by means of the Fourier Series transform and input as the lateral load. The dynamic response is obtained and compared with the measured data. The effect of the parameters such as tide heigh, diameter of the pile, distance of the pile, soil is discussed and the results are compared with other methods such as m method, constant method, static and dynamic FEM. The investigation indicates that the bore's frequency keeps away from the pile's natural vibration frequency. Though it has strong wallop, the static model of the bore is permitted to apply in design. If the length of pile in the sea is large and the natural vibration frequency is low, it's necessary to apply dynamic method, especially when the natural vibration frequency approaches the wave load frequency.