Analytical Method Of Foundation Settlement Influenced By Modulus Change And Three-dimensional Stress

Ground foundation settlement analysis is the important basis of ground treatment and foundation design, it is one of the important research of soil mechanics.However, the existing research shows that there is a big gap between the existing settlement analysis methods and engineering practice.The reason is that rationality has defects and deficiencies when considering the effects of the three-dimensional stress and the change of soil deformation modulus on the analysis of foundation settlement under the three-dimensional initial stress and three-dimensional additional stress in the study of foundation settlement analysis method.So, According to the problem that three-dimensional stress and the change of the soil deformation modulus can effect the analysis of foundation settlement. This paper will propose a new ground foundation settlement analysis method, which based on the constitutive equation of porous medium and the equivalent medium theory.Firstly, the pore properties of foundation soil are considered, and taking the foundation soil as a two-phase medium which can be abstracted into hollow spheres, consists of soil pore and soil skeleton. The relational models of the soil deformation modulus,the deformation modulus of soil particles skeleton and the soil porosity are deduced by the walsh formula and the spherical displacement formula. Then, starting from the mechanism of micro-mechanics,the concept of eigenstrain and the Eshelby equivalent inclusion are introduced, and the relationship between micro structure and macroscopic properties of soil is studied.The corresponding relation models of the soil deformation modulus,the deformation modulus of soil particles skeleton and the soil porosity are also established.Then, the nonlinear characteristics of soil deformation modulus changes are considered on the basis of the above two kinds of research, the layer-wise summation method and the step-loading method are introduced, a recurrence relation model of soil deformation modulus that under the incremental volume stress is established. Then a new method for the analysis of the final settlement of natural foundation is presented. Meanwhile, in view of the complexity of the stress and strain in the composite foundation on this basis, the interaction between pile and soil in composite foundation is considered. deformation modes of composite foundation with vertical and horizontal stacking are adopted., and the relationship between vertical and horizontal stress and strain of pile and soil in composite foundation is analyzed that is based on the generalized Hooke’s law, a new settlement calculation method of composite foundation that can reflect the interaction between pile and soil and the influence of three dimensional stress and deformation modulus is established. The method in this paper can reflect the effectsof the three-dimensional stress and the change of soil deformation modulus on the analysis of foundation settlement, and avoid the use of the compression curves of ground soils and the static load test curves of ground foundationFinally, the computation and analysis with practical engineering examples as well as comparisons between the measured and calculated settlement results by the other existing methods showed that the model and method were more reasonable and feasible.