Numerical analysis on loading transfer mechanism of geosynthetic-reinforced embankments over the Hong Kong marine deposits improved by deep cement mixed soil columns

Abstract

The loading transfer mechanism of geosynthetic-reinforced embankments over soft ground improved by piles or columns has been studied for many years. However, for most cases, the consolidation of the soft soil ground, such as the Hong Kong Marine Deposits (HKMD), with noticeable time-dependent stress-strain behavior, has not been considered before. In this study, a finite element analysis is utilized to study the loading transfer of geosynthetic-reinforced embankment over HKMD improved by deep cement mixed soil (DCM) columns during both construction and post-construction stages. Based on the numerical analysis, it is found that, in the stage of embankment construction, the soil arching develops with increasing the filling height and the limit height of arching is 1.67 times the spacing of the DCM columns. In the stage of the post-construction, the soil arching undergoes a further development and the stress concentration ratio between the DCM columns and surrounding soil increases exponentially with the differential settlement.