Dispersive soil has attracted extensive attention from the academic community due to their rapid dispersion and disintegration upon contact with water, thus affecting the stability of engineering construction. In this study, a range of tests including the pinhole test, crumb test, unconfined compressive strength test, direct shear test, moisture content test, particle size analysis, infiltration test, resistivity test, disintegration test, and scanning electron microscope examination were conducted. The purpose was to investigate the effects of varying salt content, clay content, and reservoir environmental conditions on the dispersibility, physical, and mechanical properties of dispersive soil. The test results indicated that the rise of salt content led to enhanced soil dispersion and a corresponding decrease in the soil mechanical strength. Consequently, the unconfined compressive strength of the soil samples decreased from 126.0 kPa to 94.0 kPa, and the cohesive force was reduced from 50.9 kPa to 44.3 kPa. The increase in clay content reduced soil dispersion and enhanced the mechanical strength of the soil. As a result, the unconfined compressive strength of the soil samples increased from 125.0 kPa to 298.0 kPa, and the cohesive force increased from 53.6 kPa to 122.5 kPa. In both processes, the soil liquid limit and plastic limit increase, while the coefficient of permeability and electrical resistivity decrease. This occurs because NaHCO3 enhances the thickness of the bound water film on the soil particles surfaces, which reduces the inter-particle connecting force. Clay contributes to the soil connectivity and fill the pore spaces, thereby altering the soil physical and mechanical properties. In acidic and alkaline reservoir water environments, the disintegration rate of soil samples accelerated with the increase in both acidity and alkalinity. In salt solution environments, the disintegration rate of soil samples initially increased and then decreased as the mass fraction of the salt increased. These findings offer an empirical foundation for the design of geotechnical and water conservancy projects, enhancing the comprehension of the engineering geological characteristics of dispersed soil, holding significance in both practical and theoretical realms.
