黄土钠质化对其工程性质影响的研究

土壤钠质化是我国面临的土壤问题之一。为探究钠质化对黄土基本性质的影响,以杨陵黄土为研究对象,人工配制钠盐含量分别为1、3、5、10和20 g/kg的土样,压制成不同干密度和含水率的土样,通过基本土工试验和土壤电导率测试、交换性钠离子百分比试验以及斥水性试验,分别测试钠盐含量变化对黄土基本性质的影响。结果表明:随着钠盐含量的增加,土样电导率增大,交换性钠离子百分比增大,土样钠质化程度加剧;塑限在20%左右波动,液限呈现先增加后降低的趋势;土壤斥水性随含盐量增大逐渐减弱,水分入渗变得容易,但是同时土体渗透系数降低,水体在土中渗流变得困难;同时土样的压缩系数逐渐增大,压缩变形变得容易。

Influence of loess sodication on its engineering properties

Soil sodication is one of the problems that threaten soil security. In order to investigate the effect of sodication on the basic properties of loess, Yangling loess was taken as the research object. Soil samples with artificial sodium content of 1 g/kg, 3 g/kg, 5 g/kg, 10 g/kg and 20 g/kg were prepared then pressed into samples with different dry densities and moisture contents. The basic soil test, soil conductivity test, exchangeable sodium ion percentage (ESP) test and water repellency test were carried out on these samples respectively to investigate the effects of changes in sodium salt content on loess engineering properties. It was found that the electrical conductivity and ESP of soil samples increased with the sodium salt content, which proved that the degree of soil sodication aggravated. The plastic limit of the soil samples fluctuated around 20%, and the liquid limit increased first and then decreased. The soil water repellency gradually weakened with the accumulation of salt, and the water infiltration became relatively easy, but at the same time the permeability coefficient of the soil decreased, which made it difficult for the water seepage in the soil. In addition, the compression coefficient of the samples gradually increased, so compression deformation was likely to happen.