循环荷载作用下路基粗粒土宏细观力学特性的离散元模拟

发布时间：2018-06-28 03:07

本文选题：粗粒土 + 循环荷载　；参考：《湘潭大学》2015年硕士论文

【摘要】：进入21世纪以来,国家大力发展基础建设,随着我国经济的高速发展,交通将会更便捷,越来越多的地铁、高铁将会被规划和修建。在高铁运营通车后很长一段使用期内,针对高速铁路路基粗粒填料力学性质与长期稳定性的研究已经成为一个非常迫切的研究课题。粗粒土是一种非常复杂的离散颗粒土,它不仅在国内分布广泛,它未来在工程中应用方面的研究将迫在眉睫,因此研究粗粒土的宏观力学特性与细观力学特性是大势所趋。研究高速铁路路基的长期稳定性问题,其实质就是研究循环荷载作用下,高速铁路路基粗粒土的应力——应变关系以及累计永久变形问题。从中国的高铁发展速度来看,这个研究方向将具有实际应用价值。从材料的组构方面来分析,粗粒土的力学特征很大程度上受其自身细观结构的复杂性影响,因此采用专门研究粗粒土这种离散颗粒土的PFC3D软件来探寻循环荷载作用下高速铁路路基粗粒土的宏细观力学特性具有必要性,本文主要工作如下:(1)本文将基于Akke S.J.suiker完成的高铁路基填料土的三轴压缩试验中的土颗粒级配,建立高速铁路填方路基粗粒土的PFC3D数值模型。(2)再通过与Akke S.J.suiker整理的室内三轴试验的结果进行对比分析,验证标定的颗粒流细观参数的有效性以及本文采用方法的可靠性和合理性。(3)最后对循环荷载作用下粗粒土在细观上的体积应变、偏应变、应力比、位移场的变化等进行力学响应分析。
[Abstract]:Since the twenty-first Century, the country has vigorously developed the infrastructure. With the rapid development of our economy, the traffic will be more convenient and more and more subway, high speed rail will be planned and built. In a long period of use, the research on the mechanical properties and long-term stability of the coarse grain filling of the high speed railway subgrade has become the research of the high speed railway. A very urgent research topic. Coarse-grained soil is a very complicated discrete particle soil. It is not only widely distributed in China, but it is imminent in its future application in engineering. Therefore, the study of macroscopic mechanical properties and meso mechanical properties of coarse-grained soil is a trend. The long-term stability of high speed railway subgrade is studied. In essence, it is to study the stress strain relationship and cumulative permanent deformation of coarse grained soil in high speed railway subgrade under cyclic loading. From the view of the development speed of high speed railway in China, this research direction will have practical application value. From the aspect of material composition, the mechanical characteristics of coarse grained soil are greatly influenced by its own. It is necessary to explore the macro and meso mechanical properties of coarse grained soil in high speed railway subgrade under cyclic loading. The main work of this paper is as follows: (1) the three axis compression of packed soil in high speed roadbed based on Akke S.J.suiker is presented in this paper. (1) the main work of this paper is as follows. The soil particle gradation in the test is used to establish the PFC3D numerical model of the coarse-grained soil of the embankment of high speed railway. (2) through the comparison and analysis of the results of the indoor three axis experiment with the Akke S.J.suiker, the validity of the fine parameters of the particle flow and the reliability and rationality of the method are verified. (3) finally, the cyclic loading is made. The mechanical response of the coarse-grained soil in terms of volumetric strain, deviatoric strain, stress ratio and displacement field is analyzed.
【学位授予单位】：湘潭大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U416.1

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