Research On Axial Loading-Settlement Curve Of Super-Long Bored Single Pile

With the development of super-tall building and long-span bridges, it is necessary to mass- use super-long bored piles because of their high bearing capacity. But the research on theory of super-long bored piles is far behind the development of practice. So, the research on mechanism of bearing and deformation of super-long piles is demanded. Axial loading-settlement curve of super-long bored single pile is studied in this paper.The research actuality of super-long piles and the pile calculation theory are discussed firstly and a comprehensive commentary is given. Mechanics model of pile-soil system of super-long bored single pile is put forward, pile shaft loading transfer function and pile base loading transfer function may be simplified by elastic-plastic model and elastic-hardening model respectively in order to simplification and practicality, a set of analytics of the axial loading-settlement curve of super-long bored pile in homogeneous soil are established. Based on this, the analytics of loading-settlement curve of super-long bored pile in layered soil are also established. Three dimensionless parameters of the analytics of axial loading-settlement curve are also proposed, which may be used to describe the characteristic of a pile-soil system. Meanwhile, the method of calculating the parameters of analytical equation is given.By using the great finite element method (FEM) program and the Drucker-Prager model, the pile-soil model of super-long bored pile is established, factors that influence axial loading-settlement curve of super-long bored pile under vertical loading are analyzed systemically, the characteristics of loading-settlement curve, pile shaft resistance and pile base resistance are studied, some practical guidance conclusions are acquired.With a practical engineering, a good agreement between calculation results and testing results of 1 super-long bored single pile is found, and shows the analytics established in the thesis may be used to practical engineering.