EVOLUTION CHARACTERISTICS AND MECHANISM OF SILT CLAY PROPERTIES UNDER DRY-WET CYCLE OF POLLUTION FROM LIVING SOURCES

This paper uses the mixed solution of Na₂CO₃ and Na₃PO₄ to percolate the silty clay in Xuzhou of China. It completes 10 times dry-wet cycles. The solution is a terminal product of degradation of municipal waste. The evolution characteristics of the properties of silty clay under the dry-wet cycles are analyzed, and the evolution mechanism is revealed. The results show that the permeability of silty clay increases, the resistivity decreases, the density first decreases and then rises, the cohesion and the angle of internal friction decrease, and the change of soil properties with a long seepage path has a certain lag, the dry shrinkage cracks on the surface of the soil develop and expand gradually, and the seepage path of the soil develops gradually during the dry and wet cycles. The shorter the seepage path of the soil samples, the greater the density variation of elements. The main reasons for the change of soil properties under the dry-wet cycles are the combination of seepage erosion, chemical reaction, Na⁺ion adsorption, wet expansion, dry shrinkage, and gravity infiltration.