Lateritic Soil Improved with Partially Reinforced Granular Columns Using Recycled Sand and Geosynthetics

This paper presents an innovative solution for the improvement of lateritic soils using partially reinforced granular columns. Recycled sand from construction and demolition debris was used as fill material, while a geotextile encasement, and geo-grid layers, served as partial reinforcement methods. Large-scale rigid footing loading tests were performed on different foundation systems containing granular columns and geo-synthetics. Despite the presumed advantages of the solution in terms of enhanced drainage capabilities, the use of granular columns could be linked with an increase in load capacity relative to plain foundation soil of up to 75% under 5% total strain. Nonetheless, the use of partial reinforcement methods could further enhance the load-carrying capabilities of the granular columns, i.e., up to 130% increase under 5% total strain relative to the unreinforced column. Increased foundation stiffness and the additional support provided by geo-synthetics could ultimately relate to a more efficient stress transmitting mechanism. Overall, the proposed construction technique was found to provide an economic, technical, and environmentally suitable solution for tropical and subtropical zones.