Analyzing Of The Bridge Pile In Collapsible Loess Foundation

The theory and method of calculation of pile foundation development to today, many research methods such as dependent transfer function of load transfer method, focusing on the shear deformation of the shear displacement method, applicable to the soft soil foundation of equivalent pier method and with the development of computer and mature finite element method used in this study. However, due to the need to consider the interaction between the pile and soil, the continuity of the layered soil of the pile, the influence of various factors such as the parameters and the complexity of the function, the theoretical analysis of pile foundation needs further development and innovation. The collapsible loess has special structural characteristics which causes the uneven settlement of the loess area to be threatened by a series of engineering such as bridge pile foundation, and even cause serious damage. So it is a key problem to be solved in the design of bridge pile foundation by combining the collapsible loess and the bearing capacity of the pile foundation.This paper is based on the hot issues in practical engineering, research and analysis on the collapsible loess foundation in Shan’xi province in recent years in the construction of highway bridge and expansion project. The main line of the paper is research into layers of wet Subsidence Loess Foundation under the condition of pile foundation bearing mechanism, the main target is deduced calculation formula of bearing capacity of pile foundation in summarize the research status at home and abroad on the basis, using the finite element software of wet depression of pile foundation in Loess Area carrying capacity of the system, the final results of the study for collapsibility provide theoretical basis and reference for the design and construction of pile foundation in loess area. The main research results are as follows:1. Through the research of pile foundation carrying mechanism, the bearing capacity of pile is divided for horizontal bearing capacity and the vertical bearing capacity of two aspects, and determine the analysis of vertical bearing capacity of pile foundation bearing force research focus.2. Select the representative geotechnical site parameters, establish the finite element model and analysis. The pile top load- displacement curve, axial force of pile body and pile side friction distribution curves, etc. compared with the existing model test, draw the main factors affecting the lateral bearing capacity of the pile, and the ratio of length to diameter as parameter optimization of lateral bearing capacity of the pile critical pile length calculation formula. At the same time, the main influence factors of vertical bearing capacity and the neutral point of pile side frictional resistance are also analyzed.3. According to the elastic pile side soil layer in axial semi analytical method is proposed for analyzing the bearing capacity. By giving each pile in the group piles foundation with false localization shift transfer effect of attenuation function of function and the characterization of its vertical displacement settlement, pile surrounding soil displacement passively and vertical displacement of each pile in pile group. According to the principle of virtual work with cases of differential equations, then solve the corresponding Euler equation is proposed according to the selection of boundary conditions and convergence conditions on the assumed attenuation function and displacement function of iteration method.