An Assessment Of Alternative Configurations For DCM Column-Supported Embankments To Prevent Excessive Deformations

Manasi Wijerathna and D S Liyanapathirana

T-shaped Deep Cement Mixed (DCM) columns are recently proposed as an alternative for conventional DCM columns with large area replacement ratios (ARR) over the entire depth. They alleviate the requirement of a Load Transfer Platform (LTP) used in conventional DCM column supported embankments to reduce the differential settlements and have the capacity to reduce the ARR significantly compared to conventional DCM columns. T-shaped DCM columns also improve the consolidation performance and reduce overall deformations, compared to embankments with conventional DCM columns. Therefore T-shaped columns are gaining popularity as an efficient alternative for conventional DCM columns in embankment construction. However, the performance of T-shaped DCM column-supported embankments has not been investigated in detail. Hence, in this study, the suitability of T-shaped DCM columns, geosynthetic layers and DCM column walls underneath side slopes of highway embankments in reducing deformations was investigated. The performance of different geosynthetic reinforcement configurations was compared in terms of column efficacy, consolidation performance and deformations in the ground. Although DCM column walls are generally considered as efficient in reducing lateral deformations, results show that T-shaped DCM columns are the most efficient in reducing both lateral deformations and settlements. Also, the results show that geosynthetic reinforcement is efficient only when used with conventional DCM columns with uniform cross sections but not with T-shaped DCM columns.