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 beginning of the 21st century, the country has made great efforts to develop the infrastructure construction. With the rapid development of our country's economy, the transportation will be more convenient, more and more subway, high-speed railway will be planned and built. In the long service period after the operation of high-speed railway, the study of mechanical properties and long-term stability of coarse grain filler in high-speed railway subgrade has become a very urgent research topic. Coarse grained soil is a kind of very complicated discrete granular soil. It is not only widely distributed in China, but also will be applied in engineering. Therefore, it is a general trend to study the macroscopic and meso-mechanical properties of coarse grained soil. To study the long-term stability of high-speed railway roadbed is to study the stress-strain relationship and accumulative permanent deformation of coarse grained soil under cyclic load. Judging from the speed of high-speed railway development in China, this research direction will have practical application value. From the point of view of material fabric, the mechanical characteristics of coarse grained soil are greatly affected by the complexity of its own meso-structure. So it is necessary to use PFC3D software to study coarse grained soil, which is a discrete granular soil, to explore the macro and meso-mechanical properties of coarse grained soil in high-speed railway roadbed under cyclic loading. The main work of this paper is as follows: (1) the gradation of soil particles in the triaxial compression test of high speed subgrade filler soil based on Akke S. J. Suiker will be carried out in this paper. A PFC3D numerical model of coarse grained soil in high speed railway embankment is established. (2) the results of laboratory triaxial tests are compared with those of Akke S. J. Suiker. The validity of the calibrated particle flow parameters and the reliability and reasonableness of the proposed method are verified. (3) finally, the volumetric strain, deflection strain, stress ratio of coarse grained soil under cyclic loading are studied. The mechanical response of the 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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