The Research On The Stability Of Deep-Water Pile Foundation Based On Pile-Soil Interaction

As more ports are built in the deep water off the coast and large-span structures like the bridges which cross the sea are constructed,the deep-water pile foundation, a particular form of pile foundation is more and more used. Relative to land or shallow water pile foundation,deep-water pile foundation suffers very complex loads, it is highly affected by the hydrological conditions, and a variety of adverse factors caused by deep water should be considered in the design and construction of this kind of foundation. In addition, the foundation soil is natural geological material formed for a long history, and its constitutive equations are complex and diverse. So there are a lot of problems to be solved and further studied about deep-water pile foundation.Firstly, the present research on pile and soil interaction and deep-water pile foundation at home and abroad is summarized and the basic theories involved in this paper are illustrated as well. The theories are about concrete damage plasticity model and its method of determining the parameters, and theories of the constitutive model of soil and the constitutive models of soil based on the theories. After that the importance of in-situ stress balance is also exposited.Secondly, three numerical simulating methods are given in this paper in order to study the problem of in-situ stress balance based on pile-soil interaction when single pile suffers vertical load.The numerical results before and/or after in-situ stress balance is analysed, and these results include the vertical displacement of the whole and the pile, the change of stress,the settlement of the pile under vertical load. The best one among three methods by comparing numerical experiment results with those of the code is determined. The achievement of this part will provides the important reference for the research of in-situ stress balance based on pile-soil interaction.Thirdly, the stability of deep water single pile under water flow is studied. Based on fluid-structure interaction theory and the code, the numerical simulating experiment of water flow and single pile interaction under dynamic and static is done and analysed.Lastly, the deep-water pile foundation of piled-wharf is studied. A finite element model of the front of the piled wharf is built according to the structure form and its characteristics,and loads in use period are applied to the structure. The simulations indicate the internal force and deformation of the wharf structures in design high water level and design low water level.And further, a series of numerical responses are discussed, such as the deformation of pier upper structure, the internal force of longitudinal girders, the pile foundation and representative single pile.