Abstract Stone column replacement of soft soil foundation construction method is more and more used in water conservancy projects. On the one hand, the stone column has high permeability, which enhances the dissipation capacity of excess pore water pressure; on the other hand, it has a high stiffness, which reduces the additional stress in the soil, and therefore reduces the excess pore water pressure. These two mechanisms work together to improve the bearing capacity of soil. In the previous plane strain transformation model of column-soil, only the high permeability of stone column is simply considered, while the stiffness of stone column is ignored. According to the previous research results, and based on the principle of genetic algorithm, this paper puts forward two conversion models which only consider the permeability of stone column and one conversion model which considers two kinds of action mechanism of gravel pile at the same time. The results of finite element calculation show that the transformation method considering the two mechanisms of stone columns are more consistent with the axisymmetric model.