酒精作用下上海黏性土渗透特性试验研究

Experimental Study on Permeability of Shanghai Clay under the Action of Alcohol

试验研究了酒精渗透上海原状和重塑黏性土对土体渗透特性的影响,并分析了土体骨架结构对酒精–黏性土相互作用对渗透系数改变的影响。结果表明:酒精渗透进入黏性土,介电常数的降低会使土颗粒表面电荷密度降低,扩散双电层压缩而提高了黏性土的透水性使,使黏性土渗透系数增大。土的结构性对酒精–黏性土的相互作用导致渗透性变化有一定的影响,土体为孔隙比较高的淤泥质粉质黏土时,酒精对土体渗透系数K影响更加显著,K可增大十倍;当土的孔隙较小,结构性较强时,酒精–黏性土相互作用导致的结构性变化会受到一定抑制而减弱,渗透性的变化也会随之变弱。故而破坏土体天然骨架结构,能一定程度降低酒精对黏性土水力传导性的破坏作用。因此在工程实践(如工业和有毒废物蓄积池正下方的黏土屏障)中,研究介电常数较低的有机溶液(如酒精)对黏性土渗透特性的影响需要重视土体自身骨架结构,这有助于探讨可溶性有机溶液在黏性土中的迁移过程中的相互作用。

The effects of alcohol infiltration on undisturbed and remolded clay in Shanghai on soil permea-bility characteristics were studied, and the effect of soil skeleton structure on the change of permeability coefficient of alcohol-cohesive soil was analyzed. The results show that: the pene-tration of alcohol into the clay soil, the decrease of the dielectric constant will reduce the surface charge density of the soil particles, and the compression of the diffusion electric double layer will increase the permeability of the clay soil, which will increase the permeability coefficient of the clay soil. The structure of the soil has a certain effect on the permeability change caused by the interaction of alcohol-cohesive soil. When the soil is a silty clay with relatively high porosity, the effect of alcohol on the soil permeability coefficient K is more significant, and K can increase ten times larger. When the pores of the soil are small and structurally strong, the structural changes caused by the alcohol-cohesive soil interaction will be inhibited and weakened to some extent, and the changes in permeability will be weakened accordingly. Destroying the natural skeleton structure of the soil can reduce the damage of the hydraulic conductivity of the clay to a certain extent. Therefore, in engineering practice (such as clay barriers directly below industrial and toxic waste storage ponds), studying the effect of organic solutions with lower dielectric constants (such as alcohol) on the permeability characteristics of clay soils requires attention to the soil’s own skeleton structure. It is helpful to explore the interaction of soluble organic solu-tions in the process of migration in clay soil.