The Analysis And Application Of Vertical Bearing Capacity On Large Diameter And Extra Long Pile

With the rapid development of urban construction, a variety of high-rise buildings are mushrooming.Due to its superiority,pile foundation has been widely used? At present,the outcome about small-diameter and medium-short piles is more abundant.But the research of large-diameter and long pile of research is still relatively small, the mechanism is not very clear.In this paper, the research work mainly in the following aspects:1.On the basis of the research results written by domestic and foreign scholars,the research progress and mechanical characteristics of large-diameter super-long pile has been summarized.2.In order to figure out the mechanism of pile foundations,the theoretical analysis methods of pile foundations are introduced in this paper,and the application scope of each method has been illustrated.3.To solve the ultimate vertical bearing capacity of pile foundation,the numerical analysis method has been applied.In this paper, finite element analysis software ABAQUS is the most commonly used tool.The pile-soil model is simplified as axisymmetric model due to the symmetry geometry, loads, etc. In the numerical model,the pile is using elastic model, the soil is using Drucker-Prager model to analyze the impact of factors such as pile length,pile diameter and soil modulus on the ultimate vertical bearing capacity.4. The Cosserat theory is applied to numerical simulation analysis by the UEL provided by ABAQUS,and 8-node quadrilateral ring element based on Cosserat theory is developed. We developed a theory based on axisymmetric Cosserat tetrahedral ring element, then the element is used in numerical analysis to simulate a single pile in vertical load.