Numerical Investigation On Slope Stability Of Deep Mixed Column-Supported Embankments Over Soft Clay Induced By Strength Reduction And Load Increase

The stability of the column-supported embankment may become one of the major concerns when constructed over soft clay. The numerical methods referred to as strength reduction method and the load increase method can be adopted to analyze the stability. However, limited studies have been conducted to examine the differences between load increase and strength reduction methods in the stability analysis of the column-supported embankments over soft soil. A three-dimensional (3-D) finite element method incorporated in the ABAQUS software was used in this study to investigate the contribution of deep mixed (DM) columns to the stability of the embankment over soft soil. The strength reduction method and the load increase method were implemented to obtain the factors of safety in stability. The maximum moments carried by the DM columns below the embankment crest were much less than those carried by the columns below the embankment slope. The failure modes of DM columns under embankment can be classified into four zones from the centerline to the toe, namely, compression zone, shear zone, a combination of compression and bending zone, and a combination of extension and bending zone. The factors of safety based on the strength reduction were equal to or higher than those based on the load increase.