Practical Design of Stone Column in Predicting Settlement Performance

Abstract

AbstractStone column is effective in improving soft ground. Its abilities to reduce settlement and consolidation time, increase bearing capacity and slope stability, and reduce risk of liquefaction have made it one of the most popular ground improvement techniques. End bearing columns are mostly used in the design, but occasionally floating stone columns are adopted. This paper presents simple yet practical design methods for both the end bearing and floating stone columns for large and small column group. In stone column design, the settlement and the bearing capacity are two main design criteria to be fulfilled. The settlement criterion is normally of bigger concern compared to the bearing capacity criterion for foundation on soft soils. Hence, the methods introduced here focus mainly on the estimation of the settlements of stone column improved ground. They were developed based on a series of numerical studies using 2D and 3D finite element analyses. Simulations of large column group performance were based on unit cell concept where a unit cell model was performed in 2D axisymmetric analysis. For small column group, the stone columns are simulated in three-dimensional space. Design examples are given with step-by-step guidance to ease the practitioner in the use of the methods.KeywordsStone ColumnSettlementNumerical analysis