Finite Element Analysis Of Bored Pile In Permafrost Region

This thesis presents the research status in quo and development direction of the interaction of pile foundation in permafrost in China and abroad, and establishes the research content and method. On the basis of the research method and results of the interaction of pile and soil currently, combined with the special characteristics of permafrost, the temperature change of permafrost around the pile and the interaction of single pile and permafrost are emphasized. Because of the special characteristics of permafrost, the analysis of the interaction of the bored pile foundation and the permafrost is more complicated than the usual. Utilizing the function of the thermal analysis and nonlinear mechanical analysis, the thermal and mechanical finite element models of the interaction of single bored pile foundation and permafrost are established through which the distribution of temperature in permafrost can be obtained under the consideration of the factor of time (transient thermal analysis). Meanwhile, the stress and displacement of the pile foundation in permafrost are gotten under the action of outer vertical force. All the data will be compared with the experimental data and the result of the comparison will be used to prove the validity of the finite element model and the related coefficients.The first part of the thesis mainly presents the division, practical characteristics, stress relaxation and creep of frozen soil, the temperature distribution of permafrost, and the frost-heaving force to pile foundation, the designed depth of pile foundation and the related principle of thermal transfer.The second part of the thesis is devoted to simulation method of pile body, soil and interface of the system of pile and frozen soil, and the analysis process and method of Finite Element Program ANSYS, and the thermal and mechanical models of the interaction of pile and frozen soil. In the post-processing of the simulation result, colorful figure, thermal flux figure, thermal flux gradient vector figure and cure of freezeback are utilized, which effectively analyze the freezeback process of pile and soil system; isoline, vector analysis, node analysis, path analysis of stress and strain and post-process of time-history roundly analyze the stress and strain status of pile and soil system.