Study On Erosion Resistance For Ferrous Sulfate Red Clay

Based on the comprehensive analysis on environmental geotechnical engineering, the pollution of soil and microstructure of soil abroad and at home, made clear the present problems existing in the research. And considering that the combination of Yunnan laterite is widely used and ferrous sulfate pollution abound, put forward the subject "the research on mechanical characteristics of ferrous sulfate erosion laterite". Around this topic, this paper carried out the research on mechanical, soak and microstructure characteristics of ferrous sulfate erosion laterite that lay the foundation for further revealing contaminated laterite problem.Experimental results of mechanical characteristics of erosion laterite show that the addition of ferrous sulfate increased laterite maximum dry density, optimum moisture content reduces. Ferrous sulfate concentration is lower, the curing time is shorter, shear strength and modulus of compression appeared peak, compressibility coefficient and permeability coefficient appeared valley; with the increase of ferrous sulfate concentration and curing time, shear strength and modulus of compression decreased gradually, compressibility coefficient and permeability coefficient increased gradually.The change of mechanical properties of ferrous sulfate erosion laterite can be explained from cementation and erosion the two aspects.The results of soak tests show that:after soaking, ferrous sulfate concentration is higher, silt content of the laterite increases, specific gravity decreases, shear strength and compression modulus increase after the first decrease, compression coefficient decrease after the first increases. With the increase of concentration, silt content increases overall, density increase after the first decrease. Immersion time extended, the concentration is higher, the silt content is leveling off after significant increase, specific gravity is leveling off after the first decrease and then increase. With the increase of concentration, shear strength and compression modulus of short time significantly reduce before leveling off, and compression coefficient significantly increases before leveling off, long time shear strength and compression modulus appear peak, and compression coefficient is in the valley value. Moving time extended, shear strength and compression modulus increase after the firs decrease, compression coefficient increases after the first decrease.The results of microstructure tests show that the characteristics of the microstructure of ferrous sulfate erosion laterite presents a increase of film thickness,crumb and porosity, and the variation of compactness. Small magnification, presents the overall structure of the sample. Large magnification, present a sample of characteristics such as particle, aggregate and pore. Low concentration and short time, thickness of the film increase with the increase of concentration, surface pore is not obvious. Along with the increase of the concentration and the extension of time, the film rupture.Ferrous sulfate influence on mechanical properties of laterite can be explained from cementation and erosion. Effects of the immersion of ferrous sulfate on laterite can be explained from the cement particle and sulfuric acid erosion. Effects of ferrous sulfate moving out on laterite can be explained from water erosion and the migration. The changes of mechanical characteristics, soaking characteristics and microstructure characteristics of laterite are respectively decided by the common affecting role of two aspects.