孔隙溶液对粉质黏土界限含水率的影响

针对桂林地区的粉质黏土，运用液、塑限联合测定法探讨了不同孔隙溶液作用下土体的界限含水率，并利用扫描电镜（SEM）技术从微观层面分析了水化学环境变异下土体的水化学-力学耦合作用对结构特性造成的影响。试验结果表明，随着孔隙溶液浓度的增大，粉质黏土的界限含水率均减小，且在相同浓度下同价阳离子半径较小的水溶液使得粉质黏土界限含水率下降的较为明显，随着阳离子价位的增高，其下降的幅度更大；该现象的产生主要是由于离子浓度及离子价位的增大，使得扩散双电层的厚度减小，而双电层对于土体界限含水率存在直接的控制作用。除此以外，通过探测土体的微观结构发现，水化学-力学耦合作用使得粉质黏土颗粒间发生絮凝作用，致使土粒形成粒团，土颗粒间孔隙增大，架空孔隙变多。

Effects of pore fluids on consistency limits of silty clay

The fall cone tests are performed to determine the consistency limits of Guilin silty clay under different pore fluids; and scanning electron microscope(SEM) analytic technique is used to revel the influence of the chemo-mechanical coupling interaction between water and soil under variable water-chemistry conditions on structure properties of silty clay at a micro scale. The results show that the consistency limits of silty clay would be decreased with the increase of concentration of pore fluids. Besides, it has been found that the atterberg limit decrease as the radius of cation decrease and cation valence increase, especially it’s dominated by cation valence at the same concentration. These features of the sility clay behavior can be attributed to the mechanisms of the electric diffuse double layers which would be decreased after the ion concentration and ion valence increased. What’s more, it can be seen that the flocculation among silty clay particles has been facilitated by the chemo-mechanical coupling interaction between water and soil, and it leads to the formation of granulosity and the pores between particles have been extended at a micro-level.