Settlement Calculation Theory Of Single Pile Considering Cone Angle Of Fictitious Pile And Its Application

Pile foundation is a common form of deep foundation, which is widely used in various types of buildings and structures. Since the pile foundation study is a traditional issue, domestic and foreign scholars have researched its dynamic and static characteristics deeply. But the calculation of pile settlement is still a difficult problem. The pile settlement theory can provide us with a valuable guide. However, while the behavior of surrounding soil-pile interaction has been studied quite thoroughly, the underlying soil-pile interaction is not yet. Domestic and foreign scholars prefer ignoring stratification of the pile end soils, using simplify method to solve the calculation of pile foundation settlement. But it is inconsistent with the practical engineering. Therefore, by means of the fictitious soil pile method, this thesis provides a calculation method for settlement analysis of the single pile embedded in layered soils, which can be considered in the stress dispersion of pile end soil. The principal contents and original work are as follows:Firstly, a feasibility analysis of fictitious soil pile method considers stress dispersion is conducted. Assuming soil layers under the pile end to be fictitious soil pile, and considering stress dispersion of pile end soil, it is presented in the calculation method with the load transfer method for settlement analysis of the single pile embedded in homogeneous foundation. The parameters referred in the calculation are summarized. Furthermore, the effects of length of fictitious soil pile, cone angle and segmentation accuracy on the settlement of single pile are analyzed and ranges of all these parameters are given.Secondly, based on the studies above, the settlement analysis for the linearity model of single pile embedded in layered soil is conducted using the analytical recursion method. Then, a way to calculate the length of plastic and sliding segment is also suggested. Furthermore, the settlement calculation method in layed soil for the nonlinearity model is given by the displacement coordinating method. Based on these solutions, the effects of cone angle on the settlement of single pile in layered soils are analyzed, and all the parameter ranges in different situation are given. Comparing the calculation results of this method with those of publications shows that this method is of simplicity and superiority.Finally, this method is applied to calculate load-settlement curve, axial force of pile and pile side resistance. Comparing the calculation results of this method and measured results with that of the normative method shows that this method is of practical significance to engineering. This method also can be applied to analyze the effects of the pile tip sediment and the soft soil on the pile settlement. All these studies above show that this method reflects and solves many practical pile settlement problems very well.