Numerical study of creep effects on settlements and load transfer mechanisms of soft soil improved by deep cement mixed soil columns under embankment load

Abstract

Deep cement mixed (DCM) soil columns have been widely utilized to improve soft soil to support embankments or seawalls. However, the influence of the time-dependent behavior of the soft soil on the performance of DCM column-supported embankments is not well understood. In this study, the finite element (FE) model was established to investigate the creep effects on settlements and load transfer mechanisms of the soft soil improved by DCM columns under embankment load. Comparisons were conducted for the cases of the soft soil with or without creep. The parametric analysis demonstrated that the area replacement ratio and Young's modulus of the DCM column can largely influence the long-term behaviors of the DCM column-improved composite ground. The numerical results were also compared with the results calculated by German design method (EBGEO) and British design method (BS 8006). Regarding the vertical stress taken by the DCM column, EBGEO method provides a lower limit while BS 8006 method provides an upper limit.