酸雨对丹江口库区膨胀土变形和微观结构影响研究

Study on the effects of acid rain on the deformation and microstructure of expansive soil in Danjiangkou reservoir area

为探究酸雨入渗对膨胀土边坡稳定性的影响,本文以湖北丹江口库区膨胀土为研究对象,模拟不同酸性条件(pH为3、4、5、7)开展比重试验、固结试验、X-射线衍射试验和扫描电镜试验,分析不同pH的酸雨对其比重、压缩特性、矿物成分和微观结构的影响.研究结果表明:随着pH的降低,膨胀土的比重增加,压缩系数的变化幅度增大;土中石英的含量增加,伊利石、钠长石和蒙脱石的含量有小幅度的降低;酸雨侵蚀后,膨胀土的基本单元体由片状、固体状逐渐变成絮状.

The expansive soil in the Danjiangkou reservoir area of Hubei is taken as the research object to investigate the effects of acid rain infiltration on the stability of expansive soil slopes.Specific gravity tests,consolidation tests,X-ray diffraction tests and scanning electron microscopy tests are conducted under different acidic conditions(pH 3,4,5 and 7)to analyze the effects of acid rain with different pH values on its specific gravity,compression characteristics,mineral composition and microstructure.The results indicate that the specific gravity of expansive soil increases as the pH value of acidic solution decreases.The variation ranges of compressibility coefficient increase as well.The content of quartz in soil increases.The content of illite,albite and montmorillonite decreases slightly.The basic units of expansive soil gradually varies from flake and solid to flocculent after acid rain erosion.