不同压实度黏性土微观孔隙特性与渗透性关系研究

发布时间：2018-07-04 13:26

本文选题：渗透系数 + 孔隙比　；参考：《湖北工业大学》2015年硕士论文

【摘要】：土是一种具有复杂物理性能的材料,所以人们对其物理性能的研究很多,土体的宏观特性决定了土体物理性质,而对于它的宏观特性又是由其微观结构所决定的。所以关于土体微观结构方面的研究意义非凡。渗透系数是土体宏观性能的参数之一,而土体的微观孔隙特性对土体的渗透性有显著的影响。于是在本文中,便探寻了土体的微观孔隙结构与其宏观的渗透性能之间的相关性,并通过试验以及结果分析,研究探索了宏观的土体渗透性与微观的孔隙特性之间的关系。而在研究土体微观孔隙特性与土体渗透性之间的关系时,采用变水头渗透试验与压汞试验,得到渗透系数,对土体微观孔隙特性进行分析,辅以分形理论,得到了土体孔隙的分维数,建立了渗透系数与其孔隙分维数之间的关系式。后又对试样孔隙孔径与渗透系数间的幂级数关系进行了研究,最后得到了关系式。本文所做的主要研究工作和最后的结论如下:(1)本文制备的土体试样,为取自武汉某工地的黏土,先测量其物理指标,然后风干过筛,采用静压试验的方法制备2组平行重塑试样,分别用于压汞实验与渗透试验。(2)在变水头渗透试验中,由测量数据及达西公式测得了试样的渗透系数,得到了渗透系数与孔隙比的关系曲线,可知渗透系数是随着孔隙比的增加而增大的,但其并无线性相关性。(3)再由压汞试验,测得了试样土体孔隙孔径累计进汞体积以及孔隙的分布变化规律,再结合分形理论,可知试样土体孔隙孔径具有很好的的分形特征,拟合曲线的线性相关性很好,并且孔隙体积分布分维数,是随着试样孔隙率的增大而较小,随着试样干密度的增大而增大。(4)在变水头渗透试验中,对渗透系数与孔隙率的关系研究时,可知对渗透系数k取对数之后,再与孔隙率n关系研究,得到了它们之间的关系。(5)将试样孔隙比与分维数的关系式和试样渗透系数与其孔隙率的关系式联立起来,经过转换,最后得到了试样的渗透系数与孔隙体积分维数的关系式。
[Abstract]:Soil is a kind of material with complex physical properties, so people have studied its physical properties a lot. The macroscopic properties of soil determine the physical properties of soil, and the macroscopic properties of soil are determined by its microstructure. Therefore, the study on the microstructure of soil is of great significance. Permeability coefficient is one of the parameters of macroscopical properties of soil, and the microscopic pore characteristics of soil have significant influence on soil permeability. In this paper, the correlation between the micro-pore structure of soil and its macroscopic permeability is explored, and the relationship between the macroscopic soil permeability and the micro-pore characteristics is studied through the experiments and the analysis of the results. In the study of the relationship between soil micro-pore characteristics and soil permeability, the permeability coefficient is obtained by using water head permeability test and mercury injection test, and the micro-pore characteristics of soil are analyzed with fractal theory. The fractal dimension of soil pore is obtained, and the relationship between permeability coefficient and pore fractal dimension is established. The power series relationship between pore size and permeability coefficient of the sample was studied, and the relationship between pore diameter and permeability coefficient was obtained. The main research work and the final conclusions are as follows: (1) the soil samples prepared in this paper are clay from a construction site in Wuhan. Two groups of parallel remolded samples were prepared by static pressure test for mercury injection test and permeation test respectively. (2) the permeability coefficient of the sample was measured by measuring data and Darcy formula in the permeation test of water head. The relationship curve between permeability coefficient and porosity ratio is obtained. The permeability coefficient increases with the increase of porosity ratio, but there is no linear correlation between permeability coefficient and porosity ratio. (3) by mercury injection test, The pore size accumulative mercury inflow volume and pore distribution of sample soil were measured. Combined with fractal theory, the pore size of sample soil had good fractal characteristics, and the linear correlation of fitting curve was very good. The fractal dimension of pore volume distribution decreases with the increase of porosity and increases with the increase of dry density of sample. (4) the relationship between permeability coefficient and porosity is studied in the permeability test of water head. It is known that the relationship between permeability coefficient k and porosity n is studied, and the relationship between them is obtained. (5) the relationship between sample porosity ratio and fractal dimension and the relationship between sample permeability coefficient and porosity are combined and transformed. Finally, the relationship between the permeability coefficient and the fractal dimension of pore volume is obtained.
【学位授予单位】：湖北工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU442

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