Large-Strain Nonlinear Consolidation Model of Composite Foundations Reinforced by Partially Penetrated Stone Columns and Vertical Drains

In this study, a large-strain nonlinear consolidation model is developed to analyze composite foundations reinforced by partially penetrated stone columns and vertical drains. The model employs the piecewise-linear approach and considers the self-weight effects of both the stone column and the surrounding soil, depth-dependent stress attenuation, dual smear zones (stone column and drain), well resistance, nonlinear compressibility and permeability relationships, and free/equal strain compatibility. The model demonstrates good agreement with the existing analytical solution and field measurements. Then, multiple numerical examples are presented to investigate the computational capability of the model and consolidation behavior of composite foundations with partially penetrated stone columns and vertical drains. The results show that strain conditions and constitutive relationships of soils have significant effects on composite foundations in terms of average settlement and consolidation rate; the smear effect of stone columns on the consolidation rate is more significant than that of vertical drains; and a higher penetration ratio accelerates the consolidation rate of composite foundations in the later stage of consolidation.