Deformation analysis of geosynthetic-encased stone column-supported embankments using cavity expansion model

This article presents an analytical solution to predict the deformation of geosynthetic-encased stone columns (GESCs) and the surrounding soil in GESC-supported embankments, taking into account the effect of anisotropy of surrounding soil. Based on the theory of cylindrical cavity expansion, the elastoplastic constitutive relationship of the surrounding soil is described by the K0-based Modified Cam-Clay (K0-MCC) model, analysing the relationship between the radial displacement and the elastic-plastic boundary displacement. According to elastoplastic model of stone column materials, the relationship between stress and deformation of the stone column is analysed via the radial stress and the vertical stress equilibrium. This method has been verified by the existing numerical data of GESC-supported embankments and shows a good agreement. As for the isotropic in situ stress state, the K0-MCC model-based solution of this study reduces to the MCC model-based solution of previous studies. However, the results show that the predictions generated from the isotropic model underestimate the deformation of the surrounding soil. Parametric studies are conducted to investigate the impact of the embankment fill height, the geosynthetic reinforcement stiffness, anisotropy of the soil, overconsolidation ratio, area replacement ratio, initial pore water pressure and encasement length on the deformation of GESC-supported embankments.