合肥地区非饱和膨胀土收缩性质和微观特性的试验研究

发布时间：2018-01-24 20:55

本文关键词： 膨胀土收缩性质微观特性土水特征　出处：《合肥工业大学》2015年硕士论文　论文类型：学位论文

【摘要】：合肥地区非饱和膨胀土分布广泛,膨胀土具有显著的吸水膨胀和失水收缩的特征,所以弄清其作用机理对于解决膨胀土发育地区的工程问题具有重要意义。本文以合肥地区6种非饱和膨胀土为研究对象,对其收缩性质、微观特性以及土水特征性质进行了研究。为了研究膨胀土的收缩性质,对不同初始干密度的饱和土样进行了收缩试验。研究了线缩率-含水率关系(δ-w)及孔隙比-含水率(e-w)关系,分别对这两种关系进行了曲线拟合,并根据曲线拟合结果求解了膨胀土的缩限、收缩系数、最大线缩率,分析了这些指标及曲线拟合参数与土样初始干密度的关系。为了探求试验土体的微观结构特征,对试样进行了一系列测试。通过激光法试验,得到了试样的粒径累计分布曲线,分析了试样的粒径分布特征；以压汞实验(MIP)为基础,得到了试样的孔径累计分布曲线,对试样的孔径分布特征进行了分析；用扫描电子显微镜(SEM)技术对试样的微观结构形貌特征进行了分析研究。在土水特征研究方面,对土水特征曲线进行了详细的介绍,综述了其影响因素和量测方法；重点介绍了渗析法和滤纸法,并用这两种方法对试样进行了试验研究,得到了试样的土水特征实测数据；通过拟合模型对试验结果进行了拟合分析,从而得到了较为完整的土水特征曲线及其拟合参数；以Kelvin的毛细管理论为基础,推导得到了基于土体孔径分布的土水特征曲线预测的理论方程并给出了相应的假设条件,对试验用土的土水特征曲线进行了预测,将预测结果与实测数据进行了对比分析研究。
[Abstract]:Unsaturated expansive soil is widely distributed in Hefei area. Expansive soil has the characteristics of water absorption expansion and water loss shrinkage. Therefore, it is of great significance to clarify the mechanism of action for solving the engineering problems of expansive soils. In this paper, six kinds of unsaturated expansive soils in Hefei area are taken as the research object, and the shrinkage properties of these soils are studied. In order to study the shrinkage properties of expansive soil, the microcosmic and soil-water properties were studied. The shrinkage tests of saturated soil samples with different initial dry densities were carried out. The relationship between linear shrinkage and water content (未 -w) and porosity ratio with water content was studied, and the curves were fitted respectively. According to the curve fitting results, the shrinkage limit, shrinkage coefficient and maximum linear shrinkage of expansive soil are solved. The relationship between these indexes and curve fitting parameters and the initial dry density of soil samples was analyzed. In order to find out the microstructure of soil samples, a series of tests were carried out. The cumulative distribution curve of particle size was obtained and the characteristics of particle size distribution were analyzed. Based on the mercury injection experiment (MIP), the cumulative pore size distribution curve of the sample was obtained, and the pore size distribution characteristics of the sample were analyzed. The microstructure and morphology of the samples were studied by scanning electron microscopy (SEM). The soil and water characteristic curves were introduced in detail. The influencing factors and measuring methods are summarized. The dialysation method and filter paper method are introduced in this paper. The soil and water characteristics of the sample are tested and studied by these two methods, and the measured data of soil and water characteristics of the sample are obtained. The experimental results were analyzed by fitting model, and a complete characteristic curve of soil and water and its fitting parameters were obtained. Based on Kelvin's capillary theory, the theoretical equation of soil water characteristic curve prediction based on soil pore size distribution is derived and the corresponding assumptions are given. The soil-water characteristic curve of test soil is forecasted, and the prediction results are compared with the measured data.
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU411;TU443

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