溶液作用下黏土的界限含水率及渗透试验

黏性土的界限含水率是用于土的分类和评价的重要指标,并可能与渗透系数等参数具有一定的相关性,但溶液作用下界限含水率的变化规律没有一致的结论。选取填埋场渗滤液中的几种代表性溶液,对0~15%含量的膨润土改性黏土的界限含水率及渗透性进行了试验。研究发现,CaCl₂溶液和乙酸溶液具有絮凝作用,使高液限黏土变为高液限粉土;膨润土改性黏土的液限和塑性指数与膨润土掺入量正相关;改性黏土的液限随CaCl₂溶液浓度的增大而减小;渗透系数与液限之间没有显著相关性,溶液作用下土的渗透性能还需要深入研究。

Consistency Limits and Hydraulic Conductivity of Clay under the Effect of Solution

The consistency limits are important indicators for classifying and evaluating the clay, which might be relative to hydraulic conductivity and other mechanical index. There has not been a general consensus regarding the effect of chemicals on the consistency limits of clays. Taking several solutions as the representative of landfill leachate, the consistency limits and hydraulic conductivity tests for soil-bentonite mixtures were conducted. Calcium chloride solution and acetic acid solution may result in flocculating of clay particles, and then transforming clay of CH class to that of MH class. The liquid limit and plasticity index of the mixtures are positive correlation to bentonite content. The liquid limits of the mixture decrease with the increasing of CaCl₂ concentration. There is no significant correlation between liquid limit and hydraulic conductivity. So it is necessary to further study hydraulic conductivity under the effect of solution.