中文摘要：

软土的工程特性很大程度上取决于土体内部的孔隙特征及其变化规律，为探讨软土固结过程中压缩性及其微观结构变化机理，对杭州结构性黏土进行室内固结试验，通过液氮真空冷冻干燥技术制备微观土样，借助扫描电镜试验获取微观结构图像，用计算机图像处理软件定量分析土体孔隙特征随着固结压力的变化规律，并讨论微观结构参数与土体压缩性的相关机制。结果表明：固结压力将显著改变软土的孔隙尺度、分布、排列、形态等特征，随着固结压力的增加，孔隙数先增加后减少、微小孔隙的比例增加、均一化程度提高、定向性增强、复杂程度降低；土体微观结构参数与压缩系数随着固结压力的变化规律有很好的相关性，均在固结前期显著变化，在固结后期变化趋于平缓；用土的微观结构变化解释和验证宏观试验土体的物理力学特性是可行的。

英文摘要：

The engineering properties of soft soil largely depend on the internal pore characteristics and its change rule. Compression tests for structured clay in Hangzhou were conducted to investigate the compression and its mechanism of microstructure changes during consolidation process. The samples were prepared by the technology of the liquid nitrogen freeze-dry and the microstructure images were obtained with the help of scanning electron microscope technology. At the same time, computer image processing software was used to analyze quantitatively the variation of pore characteristics at different load levels, and the correlation of microstructure parameters and soil compression were discussed. The results show that consolidation pressure significantly changes pore characteristics including scale, distribution, arrangement and pattern. With the increase of pressure, the pore number firstly increases and then decreases, the proportion of small pores increases, the homogenization degree improves, the orientation was enhanced and the complexity reduces. The microstructure parameters have a good correlation with the compression, and they both change significantly in early stage of consolidation and flatten out in late consolidation. It is feasible and applicable to use microstructure changes to interpret and validate soil mechanical behavior.