Study On The Characteristics Of Copper Sulfate Contaminated Red Soil Under The Condition Of Migration

Laterite is the specific soil type of Yunnan province, which closely related to development of this region. This article combines the phenomenon of laterite widely used in engineering construction and heavy metal substances contaminated laterite, putting forward the subject of "Research on CuSO4 contaminated laterite under different migration conditions". In the research, CuSO4 as contaminant, considering migration time, the concentration of CuSO4 solution, depth of soil column and other factors, according to migration test of soil column, physical and mechanical test, microstructure test, researching the change of physical and mechanical characteristic, microstructure feature of contaminated laterite, analysising the interaction between CuSO4 and laterite, revealling the characteristics of macro and micro correspondence of CuSO4 contaminated laterite.The physical characteristics of CuSO4 contaminated laterite shows that, the specific gravity of contaminated laterite decreases with the increasing of migration time and concentration of solution, with the change of soil column depth, the trend of specific gravity increases firstly and then decreases; the granulometric composition of contaminated laterite changed obviously. The content of coemid increasing with the migration time and solution concentration, along with the depth of soil column, the trend shows increasing firstly and then decreasing, change significantly in the shallow position of soil column. Compared with the change of content of coemid, the change of content of particle shows the opposite trend, the content of coemid and particle in large proportion of soil particle composition, they determine the composition of laterite particle and play an important influence on laterite.The migration characteristic of Cu2+ shows that time has little influence on migration of Cu2+, the position of Cu2+ will not change with the exention of migration time when Cu2+ adsorption in laterite. the greater concentration, the deeper of migration of Cu2+ and the greater concentration of Cu2+ in the same depth; with the increasing depth of soil column, the concentration of Cu2+ drastically reduced and the most of Cu2+ adsorption in the shallow layer of soil column, which shows that laterite has a strong adsorption effect on Cu2+.The shear strength characteristics of CUSO4 contaminated laterite shows that, the shear strength of laterite decreases gradually with increasing of time, and finally tend to level off; the shear strength decreases with the increasing of concentration, the greater of concentration, the more obviously effect on the shear strength; the shear strength with depth of soil column presents fluctuation change, the minimum appeared in the shallow layer of soil column; the density of laterite has obviously influence on shear strength, when the density is small, shear strength increasd obviously in shallow soil column, with increasing of density, shear strength changed gently. While in deep of soil column, there is a positive correlation between shear strength and density of laterite.Microstructure feature of CuSO4 contaminated laterite shows microstructural parameters can reflect change of microstructure, such as porosity, the number of soil particles, fractal dimension, complexity and circularity. With the exention of migration time, porosity, fractal dimension and complexity show increasing firstly and then decreasing, while the number of soil particles and time are positively correlated. With the pollution concentration increasing, porosity and fractal dimension will increase, circularity will decrease, complexity decrease alternately. With change of depth of soil column, porosity and fractal dimension will decrease, the trend of complexity is increasing and then decreasing, however, circularity shows no clear trend.The interaction between CuSO4 and laterite shows that the characteristics of macro and micro of contaminated laterite changed obviously, material composition had changed and stable structure damaged. The interaction between CUSO4 and laterite includes hydrolysis, erosion, cementation and dissolution, changing of the characteristics of macro and micro of laterite is the result of these four effects. According to analysise the interaction between pollutants and laterite, which can understand the migration mechanism of pollutants well and effectively control diffusion of pollutants.