浑水颗粒级配对一维入渗规律及致密层形成特性的影响

Effects of Muddy Water Particle Gradationon on One-dimensional Infiltration Law and Characteristics of Tight Layer Formation

为探明浑水不同泥沙颗粒级配对入渗规律及致密层形成特性的影响,通过室内土柱垂直入渗试验,选取4种不同物理性黏粒含量的泥沙(5.59%,9.87%,18.43%,39.43%),研究落淤层厚度、湿润锋运移距离、累积入渗量随入渗时间变化特征,并测定落淤层和入渗结束后不同深度(0—1,1—2 cm土层)土壤的颗粒级配。结果表明:浑水泥沙中物理性黏粒含量越大,落淤层厚度越大;同一入渗时刻湿润锋运移距离和单位面积累积入渗量随物理性黏粒含量的增大而减小。落淤层厚度随时间变化符合幂函数关系(R2>0.9),拟合系数随着物理性黏粒含量的增大而减小,而拟合参数在0.50上下变化。不同物理性黏粒含量下落淤层与入渗泥沙颗粒组成相似,2 cm入渗深度处土壤颗粒组成与原土壤类似;1 cm入渗深度处土壤<2 mm细颗粒含量较原土壤变大,随着物理性黏粒含量的变大,各处理分别增加4.29%,4.92%,7.96%及16.30%。研究结果可为进一步探究浑水入渗形成致密层特性提供理论依据。

Inorder to explore the influence of different particle gradations in muddy water on the infiltration law and formation characteristics of tight layer,indoor vertical infiltration experiments of soil pillars were conducted.In this study,four types of sediment with different physical clay content(5.59%,9.87%,18.43%and 39.43%)were selected and the variation characteristics of the thickness of the falling silt layer,the wet front migration distance and the cumulative infiltration volume with the infiltration time were studied,and the gradation of soil particles in the falling silt layer and the different depths after the infiltration(0—1 cm,1—2 cm)were measured.The results showed that the greater the content of physical clay in the muddy cement sand was,the greater the thickness of the falling silt layer was.At the same infiltration time,the migration distance of the wet front and the cumulativ e infiltration amount per unit area decreased with the increasing of the physical clay content.The variation of the falling silt layer thickness with time conformed to the power function relationship(R2>0.9),and the fitting coefficient decreased with the increasing of the physical clay content,and the fitting parameter changed around 0.5.Under different physical clay contents,the particle composition of the silt layer was similar to that of infiltration sediment.The particle composition of soil at 2 cm infiltration depth was similar to that of the original soil.The content of fine particles<2 mm in the soil at 1 cm infiltration depth increased compared with the original soil.With the increasing of physical clay content,the contents of fine particles<2 mm increased by 4.29%,4.92%,7.96%and 16.30%in different treatments,respectively.The research results could provide a theoretical basis for further exploring the characteristics of dense layers formed by muddy water infiltration.