Abstract: Based on the piece-linear finite difference approach, a nonlinear consolidation model, called SC1, of stone column composite foundation considering large strain was developed. The model has the ability to analyze the consolidation of pile-soil composite foundation under the conditions of free stress and equal strain, and to consider well resistance, smear area, self-weight of pile-soil, variable load, as well as the nonlinear changes of pile-soil parameters in the consolidation process. The model was validated against the equal strain analytical solution and experiment. Under the condition of small strain, the numerical solutions of the model are in good agreement with the analytical solution of pile-soil composite foundation with or without well resistance and smear area. Under the conditions of large strain and nonlinear consolidation, the model calculation results are basically consistent with the experiment data. Then, the model was used to predict a practical engineering, and it was found that with the extension of consolidation time, the difference between the calculated values of the model based on free stress and equal strain increases gradually, and the field measured value is between the numerical solutions of the model with free stress and equal strain.

Key words: composite ground, stone column, large strain, nonlinear, consolidation model