Simplified Analysis Method of Stone Column Reinforced Foundations Based on Homogenization Technique

Stone columns are a resultful measure to increase the bearing capacity of soft or liquefiable foundations. The centrifuge model test and finite element method were employed to investigate the bearing capacity and deformation behavior of the stone column-reinforced foundation. Study shows that the modulus of the reinforced foundation exhibits significant anisotropy. A bulging deformation area is identified in the reinforced foundation where obvious horizontal deformation of the stone column occurs. The ratio of the column stress and soil stress is observed to change violently in this area. A homogenization technique is consequently deduced by employing the column-soil stress ratio as a key variable. The definition of the column-soil stress ratio is extended to reasonably describe the column-soil interaction under different stress levels and its approximation method is given. Based on the Duncan- Chang E-ν model, a simplified method using the homogenization technique is proposed for the stone column reinforced foundation. The proposed homogenization technique and simplified method have been validated by the centrifuge model tests and finite element analyses. This method properly addresses the nonlinear spatial characteristic of deformation and the anisotropy of the stone column reinforced foundation.