【作者】 朱德举；

【导师】 贾艳敏；

【作者基本信息】 东北林业大学 ， 道路与铁道工程， 2004， 硕士

【摘要】 本文首先介绍了国内外对于多年冻土、桩土相互作用的研究现状和发展趋势，明确了本文的研究内容和方法。借鉴当前桩-土相互作用问题的研究方法和成果，结合冻土自身的特殊性质，重点解决桩周围冻土的温度场变化和单桩与多年冻土的相互作用问题。由于多年冻土自身的特殊性，多年冻土-钻孔灌注桩相互作用问题更加复杂，本文运用ANSYS的热分析和非线性力学分析模块功能，建立单桩-多年冻土相互作用的热学和力学模型，求得在考虑时间因素的情况下(瞬态热分析)多年冻土温度场的分布情况。同时，确定多年冻土中的桩基础在竖向外荷载的作用下，桩基础的应力状态和位移分布情况，并与现有试验资料相比较，验证有限元模型和相关系数的正确性。 第一部分重点介绍了冻土类型划分、工程特性、应力松弛和蠕变现象、多年冻土的温度场分布、多年冻土对桩基础的冻胀力、桩基础埋置的设计深度和传热学方面的相关理论。 第二部分论述了桩-土体系中桩体、土体和接触面本构行为的数值模拟方法；利用ANSYS进行分析的过程和方法；并建立了钻孔灌注桩与冻土相互作用的热学和力学模型。在数值模拟结果后处理部分，利用温度场的彩色云图、热流量图、热流梯度向量图和回冻曲线，有效地分析了桩-土体系的回冻过程；利用等值线、矢量分析、选定节点分析、应力与应变路径分析、时间历程后处理，比较全面地分析了桩-土体系的应力和应变状态。更多还原

【Abstract】 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.更多还原