Loess Deep Foundation Finite Element Analysis Of Stress Field

The research on technique and theory of deep foundation pit engineering in loess area is at the stage of start. So, the following questions such as: how to simulate the process of excavating and retaining of the deep foundation pit engineering, how to calculate and analyze the pressure and deformation of the surrounding soil, how to calculate and analyze the deformation of retaining structure in the course of excavating, how to predict the earth subsidence and the swelling of pit bottom, and how to predict the deflection of surrounding pipes in loess area, are all worth researching. This paper is titled as "analysis of the stress field of deep foundation pit engineering in loess area by finite element method", and it aims at simulating the process of excavating and retaining of the deep foundation pit engineering, calculating and analyzing the pressure and deformation of the surrounding soil, and the deformation of retaining structure in the course of excavating in loess area. Thus, this paper provides a theory base for foundation-retaining-structure design, which aims at deflection-control.In this paper, 8-node isoparametric quadrilateral element is used to divide the soil and retaining structure. Comparing to practical engineering, the numerical method-finite element method is used to analyze every behavior of deep foundation excavating and retaining in loess area. The following work has been done: nonlinear-elastic and the elastic-plastic analysis on excavating of deep foundation pit step by step using the finite element method, and the same to the elastic-plastic analysis with considering the process of saturating in loess area. At the same time, programs-HTKWTX.f, HTKWSX.f and HTKWJS.f are designed to analyze the variation of the stress and displacement field during excavating of the practical deep foundation pit engineering "shannxi information building". Then the outcome of calculation is visualized by MATLAB language. At last, the law of deformation of pit bottom and surrounding surface in different stress state and in different excavating step is obtained, and the same to the saturating process of surrounding soil. To some extent, in predicting the deformation of surrounding soil and retaining structure in construction, in preventing the foundation pit accident from happening, in insuring the security of environment and regular use of pipes underground, and in giving advice to deep loess foundation pit engineering in practice, the conclusion is of theoretical and practical value.