Effect of the driving process for construction of geotextile-encased columns on the deformation of soft foundation soils

The construction of geosynthetic encased columns for embankment support involving the tube driving technique may induce vertical and horizontal stresses throughout the soft soil foundation and neighboring columns, which is often not accounted for in design. Investigating this unknown effect is a difficult task for which the use of the transparent soil method is a promising tool when combined with Digital Image Correlation (DIC) techniques. This study investigates the effect of GEC column installation on the deformation of the soft foundation soil. The specific focus is on how the driving process affects the lateral and vertical deformations of the surrounding soft soil, as well as the interaction with neighboring columns. Different column configurations, spacing, and installation sequences were investigated. After evaluation and quantification of the deformation patterns, a methodology is proposed to study the extent of displacements caused by the tube's driving. Results showed that an increase in the spacing between columns reduced the influence of the tube's driving. Interestingly, adopting the alternating GEC installation may lead to higher lateral displacements than the sequential installation process. Increasing the number of GECs from three to four elements further reduced the displacements magnitude in the region adjacent to the first column installed.