The Study of Improved Silty Sand with Stone Columns under Consolidation Condition

In a laboratory setting under consolidation conditions, this study investigated the performance of saturated silty sand improved by stone columns. The studies were carried out with area replacement ratios of 0.03, 0.06, and 0.11, and relative soil densities of 40% and 90%. The properties of the stone column were analyzed by measuring settlement and stress distribution on the soil and column. The performance improvements are mainly due to the stiffness and high bearing capacity of silty sand under dry conditions. However, when in contact with water, there is a high risk of failure because the soil becomes saturated or partially saturated. The soil transitions from a solid to a liquid state, resulting in a loss of strength and stiffness under applied vertical pressure. The test results displayed that the settlement reduction ratio of the stone column ranged from 1.12 to 2.18. The stress concentration ratio ranged from 5.04 to 6.78, and column efficacy ranged from 0.126 to 0.459. Thus, the stone column significantly improved the silty sand by decreasing settlement, increasing stress on the column-supported embankment, and reducing stress on the soil.