A test study of the characteristics of chemical reaction between purple unconsolidated soil and water in different saturated environment

A kind of special purple soil, which widely occurs in the Three Gorges region, was selected as the object of this study. They were immersed in five different aqueous solutions. According to the minimum energy principle and linear programming, the thermodynamic reaction model was established to analyze the rules of water-soil chemistry interaction in these saturated processes. The results showed that the major soil-water interaction types changed with time in different solutions. Dolomite minerals composition mainly dissolves in river water and alkaline solution and calcite minerals composition dissolution and Ca-K icon exchange adsorption mainly occur in tap water, pure water and acidic solution. The most intense chemical interaction occurs between soil and acid solution at the saturated time of 1-7 days, and others are at the time of 7-16 days. Finally, in the five different solutions, all water-soil chemistry interactions weakened and tended to equilibrium.