Numerical evaluation of deep soil mixed column on performance of embankment over soft clay

Abstract

Deep soil mixed columns (DSMC) are emerging as an alternative to other ground improvement methods for construction of embankments over soft clay layers. However, limited studies have explored the effect of variation of DSMC parameters, viz., diameter, length, elastic modulus, and spacing/numbers, on the performance of DSMC-modified soil. The present numerical study, using PLAXIS 3D, evaluates the effect of various DSMC parameters on settlement and excess pore water pressure characteristics for 12 kPa loaded embankment supported on thick soft clay strata. The study observes that the inclusion of DSMC results in a significant reduction in settlement of clay layer by 68.7–87.6%. This can be attributed to significant load sharing by DSMC, reducing the pressure in soil significantly. This has been confirmed by substantial reduction in excess pore water pressure induced due to embankment loading. Further, the settlement ratio reduces from 1.73 for soil without DSMC to 1.38–1.54 for different cases of soil with DSMC. This suggests that long-term soil settlement is reduced substantially due to the inclusion of DSMC. Overall, the findings are quite useful in demonstrating the benefits of DSMC as rigid inclusion in soft clay, which can be an alternative solution to various other ground improvement methods.