中文摘要：

压实膨胀黏土常用于防止填埋场中固体废物产生二次污染，或作为核废料处置库通道隔绝层，这主要取决于压实膨胀黏土衬垫层或隔离层的防渗特性，而这种压实膨胀黏土层通常又呈现出非饱和特性。基于GDS非饱和土三轴试验系统，开发拓展其试验功能，研究直接测量压实膨胀黏土的水渗透系数的试验方法，同时结合电镜扫描试验，从微观角度定量分析压实膨胀黏土渗透过程中产生的微观、宏观变化特征。结果表明，压实膨胀黏土在渗透过程中产生的体积变形主要是由于土孔隙中气体被压缩、孔隙微结构发生变化的结果；压实膨胀黏土水渗透系数受吸力、围压、干密度、饱和度等因素控制。

英文摘要：

Compacted expansive clay is widely used as impermeable material of liner in the garbage landfill and prevention fill of nuclear waste material treatment. The permeability characteristics of expansive clay will effect on anti-seepage effect of liner cushion clay. Due to the difficulty of measuring permeability coefficient directly, the parameter is also evaluated by indirect method which is hard to truly explain permeability characteristics of unsaturated soil and phenomenon of migration of water. This paper discusses measuring permeability coefficient directly by GDS system and quantitatively analyses the influence of structure by permeability test and the SEM test which show the micro and macro-structure characteristics in the permeability process. The results show that the volume deformation of unsaturated expansive soil in permeation process is due to pore air is compressed and changes in pore structure. The pore water permeability coefficient of unsaturated expansive soil is controlled by suction, cell pressure, dry density and degree of saturation of soil samples.