邢衡高速软弱土微观结构特征研究

发布时间：2018-06-12 13:59

本文选题：土体微观结构 + 结构参量　；参考：《河北工业大学》2014年硕士论文

【摘要】：对于穿越古湖泊湿地地区的邢衡高速公路，沿线厂泛分布着软弱土，该地区受地形地势和气候降水等自然因素的影响，具有区别于东部沿海平原地区软土的特卢。大量的研究和实践证明，，土体的工程性质除了与其物质成分、颗粒分布等密切相关外，其微观结构因素如颗粒形状、分布、排列和连结方式、孔隙尺度及孔隙本等也起到支配和控制作用，软土微结构的复杂性和随机性导致其宏观上力学性质的复杂性和随机性。本文通过试验，利用扫描电子显微镜和分形理论研究了土体不同应力状态下的微观结构。主要研究内容和成果如下： (1)通过对邢衡高速沿线软弱土原状土进行室内土工试验以及X射线衍射试验,得出邢衡高速软弱土的基本物理力学性质、矿物成分组成以及颗粒组成。采用电镜扫描(SEM)测试技术，对邢衡高速沿线内在不同应力路径下的软弱土原状土样的水平截面和垂直截面微观结构特征进行了观测，分析不同应力下土样的微观结构特征。 (2) 土体微观结构的参量提取与定量分析。利用土体微观结构图像数据提取出表达土体微观结构特征的参数，如颗粒等效粒径、数量、圆度等，分析了不同应力状态下土样水平截面与垂直截面的微观结构参数，揭示了不同应力状态下的软弱土各自微结构参数随压力的变化规律，从而阐述土体发生宏观变形的微观机制。 (3)基于分形理论适合于研究复杂不规则图形的特卢，本文运用分形理论对土体的微观结构进行了深入分析。同时，针对本次研究内容的特卢，定义了研究土体中孔隙和颗粒分布状况的平面分形维数。利用MATLAB语言编写程序，对土体微观结构图片进行了平面分维计算，分析不同应力状态下试验后土体微观结构的分形特征。
[Abstract]:For Xingheng Expressway crossing ancient lake wetland area, soft soil is widely distributed along the highway, which is different from the soft soil in the eastern coastal plain by natural factors such as topography and precipitation. A large number of researches and practices have proved that the engineering properties of soil are closely related to its material composition and particle distribution, and its microstructural factors such as the shape, distribution, arrangement and connecting mode of particles. Pore size and pore size also play a dominating and controlling role. The complexity and randomness of the microstructure of soft soil lead to the complexity and randomness of its macroscopic mechanical properties. In this paper, the microstructure of soil under different stress states is studied by means of scanning electron microscope and fractal theory. The main research contents and results are as follows: 1) the basic physical and mechanical properties of Xingheng high speed soft soil are obtained by indoor geotechnical test and X-ray diffraction test. Mineral composition and particle composition. By means of scanning electron microscopy (SEM) technique, the microstructural characteristics of horizontal and vertical sections of undisturbed soft soil samples along Xingheng high speed line under different stress paths were observed. The microstructural characteristics of soil samples under different stresses are analyzed. The parameters of soil microstructure such as equivalent particle size, quantity and roundness are extracted from the image data of soil microstructure. The microstructure parameters of horizontal and vertical sections of soil samples under different stress states are analyzed. In this paper, the variation law of microstructural parameters with pressure of soft soil under different stress states is revealed, and the microscopic mechanism of macroscopic deformation of soil is expounded. Based on fractal theory, it is suitable for studying complex irregular patterns. In this paper, fractal theory is used to analyze the microstructure of soil. At the same time, the plane fractal dimension of pore and particle distribution in soil is defined in this paper. In this paper, the fractal dimension of soil microstructure is calculated by MATLAB language, and the fractal characteristics of soil microstructure under different stress states are analyzed.
【学位授予单位】：河北工业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U412.22

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