Behavior of Geosynthetic-Encased Stone Columns in Soft Clay: Numerical and Analytical Evaluations

The type of improvement technique that will be applied to a soil beneath an embankment depends on the nature of the problematic soil existing at the site. Soft soils beneath embankments typically present high compressibilities and low shear strengths. In some cases, geosynthetic-encased stone columns (GECs) have shown advantages over other solutions to improve embankment behavior. The aim of this study is to investigate the performance of GECs by means of numerical and analytical methods. Finite Element Analyses were conducted to evaluate the behavior of ordinary and geosynthetic-encased stone columns underneath an embankment. Parametric studies were then conducted to investigate the influence of geosynthetic stiffness, column spacing, friction angle of column material and Stress Concentration Ratio (SCR) on the performance of the columns. The results obtained have shown that there are several parameters that are of paramount importance in improving the performance of GECs, such as geosynthetics stiffness, column spacing and thickness of soft soil layer.