Evaluation of Stability of Embankment Constructed on Soft Consolidating Soil with Lime–CFG Composite Column System

Effectiveness of providing lime and CFG composite column system on the safety factor of embankment constructed on consolidating soil is studied at different time intervals during consolidation of foundation soil. The effectiveness of providing composite column system is compared with the effectiveness of providing only lime or CFG columns. In addition, the effectiveness of composite column system on settlement of foundation soil and consolidation process is also investigated. Embankment, foundation soil and columns are modeled using finite element method. Numbers of trial surfaces with different center and radius are generated at each time interval and the critical surface is selected to calculate the safety factor using the effective stresses obtained by finite element analysis. From the study, it is concluded that provision of lime or CFG columns, either individually or in combination, reduces the settlement and improves the safety factor. However, the most effective type of columns and their arrangement to reduce the settlement may not be the most effective to enhance the safety factor and hence, the type of columns and their arrangements has considerable influence on the purpose for which columns are provided.

Force and Settlement Characteristics of an Embankment on Soft Consolidating Soil with Lime Columns

Embankment supported on soft soil with lime column is analyzed. The lime column is modeled using a two noded plane frame element with three degrees of freedom (DOF) (two transnational and one rotational), whereas the soil stress- strain behavior is presumed to be non-lining and modeled by a Cam-Clay model. The properties of lime column is obtained from a stress- strain curve obtained from a laboratory test. It is concluded from the study that addition of lime column in soft soil reduces the settlement after the construction.