Abstract: The modification and utilization of dispersed soil are critical issues in geotechnical engineering. The traditional modification with lime has a high cost and environmental damage and other adverse effects, so it is urgent to explore new treatment materials and technologies. Based on this, aluminum compounds and traditional special soil modifier(lime) were used to treat the typical dispersive clay in a homogeneous dam in northeastern China. The effects of different types and contents of modifiers on the physicochemical properties, dispersibility and mechanical properties of dispersive clay were investigated. The microscopic mechanism and modification mechanism of modified dispersive clay of aluminum compounds were studied by microscopic experiments such as scanning electron microscopy. The results show that when the lime content reaches 1%-3% or the aluminum compounds content reaches (2～4)×10?4 mol/g, both of the two modifiers show good modification effect and can improve the shear strength of the dispersive clay. Lime has no obvious effect on the particle composition of the soil. With the increase of lime content, the pH value of the dispersed soil increases and the dispersibility is effectively suppressed. The aluminum compounds can change the particle composition of the soil by agglomeration and cementation with the soil. Meanwhile, it can effectively reduce the pH value of the soil, which can achieve excellent improvement effects. Compared with lime-modified dispersive clay, aluminum compounds-treated soil has high application value in practical engineering with the advantages of environmental friendliness, convenient construction and in-situ treatment.

Key words: dispersive clay, aluminum compounds, lime-treated soil, dispersion identification test, shear strength