An Embankment Stability Analysis Using Finite Element Method Constructed over Soft Consolidating Soil Improved from Lime Columns and Prefabricated Vertical Drains

The effectiveness of lime columns to improve the stability of embankment constructed on soft consolidating soil is investigated. Along with this, the effectiveness of prefabricated vertical drains (PVDs) with lime columns is also compared. Further, the combination of lime columns and PVDs is also studied to improve the embankment stability on consolidating soil. A numerical study is carried out using two-dimensional plane strain finite element method. To study the effectiveness of lime columns on the embankment stability, the foundation soil settlement, excess pore water pressure and factor of safety for embankment are obtained at various time intervals during consolidation of foundation soil. This study shows that the settlement and excess pore water pressure decrease, and the factor of safety increases due to the provision of lime columns. Also, the settlement is lesser, and the factor of safety is larger for soil with lime columns compared to soil with PVDs, whereas, excess pore water pressure dissipates faster in soil with PVDs compared to soil with lime columns. This study concludes that, compared to PVDs, lime columns are more effective to improve the embankment factor of safety and foundation soil settlement, whereas PVDs are more effective in accelerating excess pore water pressure dissipation. The lime columns and PVDs combination is observed to be effective to improve all parameters.