Study On The Property Structure And Migration Mutual Feedback Characteristics Of Silty Clay Under The Action Of CH₃COOH Contaminant Seepage

Contaminated materials constantly change their properties and structures in the process of soil seepage.On the contrary,the properties and evolution of soil will also affect the characteristics of seepage migration.The two effects are carried out simultaneously and affect each other.In order to study the seepage effect of domestic pollution in soil and its mutual feedback relationship with soil property structure,silty clay in Xuzhou area was taken as the research object,and CH₃COOH,the main component in the degradation process of domestic pollution,was selected as the pollution.The mutual feedback test system composed of the first and second stages of mutual feedback was established.On the basis of testing and analyzing the dynamic evolution law of soil property structure under different axial compression and seepage pressure,the migration characteristics of the two stages of mutual feedback were studied with the migration quality and migration rate of CH₃COOH solute as the parameters,and the mutual feedback relationship and mechanism of soil property structure and migration under the seepage effect of CH₃COOH pollution were revealed.The study shows that:（1）In the process of CH₃COOH pollutant seepage,the dry density,void ratio,shear strength and permeability coefficient of silty clay change significantly under the action of pollutant seepage.（2）The characteristics of CH₃COOH contaminant transport in the first stage of mutual feedback:With the increase of seepage path length,the mass concentration and conductivity of CH₃COOH contaminant increase,and the change rate increases;With the increase of seepage migration time,the mass concentration and conductivity of CH₃COOH pollutants increased,and the change rate showed a decreasing trend.（3）CH₃COOH transport in the second stage of mutual feedback is obviously affected by the change of soil structure in the first stage of mutual feedback.Pollutant content and conductivity were positively correlated with migration time and negatively correlated with seepage path length;The change rate of pollutant content is positively correlated with the migration time and negatively correlated with the seepage path length.The change rate of conductivity increases first and then decreases with the migration time,and the change law is not obvious with the seepage path length.In soils with lower porosity and permeability,the time of CH₃COOH contamination reaching the same position is later.（4）Compared with the first stage of mutual feedback,in the second stage of mutual feedback,the decrease of void ratio and permeability in contaminated soil hinders the migration and diffusion of CH₃COOH pollutants,and its inhibitory effect increases with the increase of seepage path length;The soil characteristics with larger void ratio and permeability promote the migration of CH₃COOH pollutants,and the effect decreases with the increase of seepage path length.（5）The mechanism of soil property structure and migration under the seepage of CH₃COOH pollutants is that CH₃COOH pollutants react with soil chemically.CH₃COOH pollutants make soil pores more developed by dissolving the mineral composition of soil and weakening the thickness of soil particle double layer,thereby enhancing the migration of pollutants.At the same time,the ion exchange adsorption,adhesion and sedimentation between CH₃COOH pollutants and soil will hinder the migration of pollutants in soil.This paper has 54 figures,13 tables and 121 references.