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利用疏浚土有机质含量高、吸附能力强和低渗透性等特点,探讨将其作为填埋场黏土衬垫改性材料的可能性。针对粘土垫层所关心渗透性及强度两个基本问题,比较了粉质黏土、改良土(粉质黏土添加疏浚土)吸附离子前后的变化。吸附K+、Cu2+后粉质黏土、改良土的渗透系数随着土中离子含量的增加而增大,但对改良土渗透系数的影响要小于粉质黏土;吸附离子后,粉质黏土摩擦角增幅不大,黏聚力有较大增长,而改良土的黏聚力增长较少,摩擦角增长较快。总体而言,添加一定量的疏浚土能改善吸附离子对黏土垫层的影响。采用SEM电镜试验拍摄了离子吸附前后土体微观结构的变化,并从扩散双电层理论出发,解释了吸附离子对粉质黏土及改良土的影响。
Using the characteristics of high content of organic matter, strong adsorption capacity and low permeability of dredged soil, the possibility of using it as a modified material for clay liner in landfill is discussed. In view of the two basic problems concerned with permeability and strength of clay cushion, the changes before and after the adsorption of silty clay and modified soil (dredging soil with silty clay) were compared. After adsorbing K +, Cu2 +, silty clay, the permeability coefficient of modified soil increases with the increase of ion content in soil, but it has less effect on the permeability coefficient of modified soil than that of silty clay. After adsorption of ions, the increase of friction angle of silty clay Not large, cohesion greater growth, and improved soil cohesion less growth, friction angle increased rapidly. In general, adding a certain amount of dredged soil improves the effect of adsorbed ions on the clay cushion. The changes of the microstructure of the soil before and after the ion adsorption were photographed by SEM electron microscopy. Based on the theory of diffusion electric double layer, the influence of adsorbed ions on silty clay and modified soil was explained.