| The large amount of sediment in the coastal area of China is mainly silt soft soil and its mechanical properties include large void ratio, high water content and the frequent occurrence of unconsolidated property. The sedimentary soil for agriculture infrastructure, because the foundation is weak, so they often uses the pile foundation.In the solidification process of the unconsolidated soil, there will cause settlement of the foundation soil, negative frictional resistance and down drag on pile, pile body damage and foundation destruction of the pile tip. And once the foundation settlement range is larger, it can make the cap bottom and foundation soil separate from each other and lead to the phenomenon of cup void. In addition, foundation settlement may also have an impact on the adjacent buildings and cause the later to incline or crack, which may lead to serious engineering accident. Therefore, we need to study the negative friction problem of pile body and the problem of ground subsidence in soft soil.This paper aims to present a new type of pile- spindle type pile, study the characteristics of pile side negative friction and technological application of controlling ground subsidence. The present author firstly conducts theoretical analysis of the features of the negative friction of spindle-type pile according to the pile shape and the force situation. Then the three-dimensional finite element computing model of spindle type pile and single pile with uniform cross section will be established applying ABAQUS software. Through the numerical simulation analysis, several main influencing factors of negative friction of pile side such as friction coefficient, inner friction angle of the soil, cohesion force, pile top load, surface loading and soil consolidation time, etc. Will be investigated. by comparing the advantages of spindle type pile with pile with uniform cross section, the research results indicate that the wedge angle of spindle type pile is conducive to the reducing of negative friction of pile, the improving of the bearing capacity of pile foundation and the reducing of ground settlement. Finally, the paper introduces the structure design, working principle and interaction mechanism of pile and soil. It shows the superiority of spindle pile in controlling ground settlement and preventing cushion caps void and points out that the spindle type pile is worthy of popularization and application.The study on a new type of spindle type pile will be an innovative research work. This pile has high bearing capacity, simple model and convenient construction type and the appropriate application of this technology can save materials, improve the bearing capacity and effectively reduce the influence of negative skin friction on pile. And it has significant theoretical value and engineering significance for the construction and use of agricultural facilities in unconsolidated soil. The command of the technology of controlling ground settlement can better reduce the engineering risks and ensure the safety of people’s life and property; therefore, this research has high academic value and engineering application value. |
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