Analysis of Railway Embankment Supported with Geosynthetic-Encased Stone Columns in Soft Clays: A Case Study

Construction on soft soils is a promising task, as it is necessary for engineers to overcome challenges of excess settlements and possible bearing failure. This paper deals with proposing a suitable ground improvement technique as a remedy for an already failed railway embankment and evaluating the performance of the proposed technique both in short- and long-term periods. Based on the prevailing site conditions (i.e. poor shear strength) and obligatory to complete the work within the stipulated time, it is found that geosynthetic-encased stone column (ESC) is a preferred ground improvement technique. An extensive 2D finite element analysis has been undertaken to examine the improvement in bearing capacity concurrently addressing slope stability problem for different column spacing of 1.5, 2, 2.5, 3, 3.5, and 4 m. Interpretation of results revealed that bearing capacity and stability are critical in the short-term period. The results further demonstrated that ESCs by undergoing lateral deflection and bulging, which are found to predominate in the short-term period, sustained the failure against bearing capacity and stability. The spacing of 3 m when considered bearing capacity alone and 2.5 m corresponding to lateral deflection alone is found optimal. Based on the outcome of the study, it is demonstrated that the proposed ESC is an ideal solution of ground improvement for the present case study of failed railway embankment.