Effect of Configuration and Spacing on the Load-Carrying Capacity of Stone Columns

The stone column is an effective ground improvement technique for extensive areas. In general practice, stone columns are arranged in a triangular or square pattern with spacing two to three times their diameter. A comparative study has been conducted on stone columns of varying sizes and patterns while maintaining the same area ratio. The singular larger stone column was transformed into one, two, three, and four columns maintaining the same area ratio, and load settlement analysis was conducted using experimental models. Also, the effect of spacing between columns was analysed for the stone column with triangular and square configurations. Experimental models were constructed in a circular test tank with a soft soil bed reinforced by stone columns. The test results indicated that the configuration of three stone columns arranged in a triangular pattern exhibited the highest bearing capacity among all configurations. Configurations featuring more than three stone columns exhibited a diminished load-carrying capacity, a trend also observed with fewer stone columns. The bulging effect of the stone column supported the soil enclosed by three columns and a group of columns along with the enclosed space acts as a composite column. This analysis indicates that the stone column can be optimised in terms of size and configuration according to the performance requirements of the stone column.