Analytical Method for Estimating the Bearing Capacity of Stone Column Groups

Owing to their ease of implementation, cost-effectiveness, and environmental compatibility, stone columns (SCs) are widely utilized in geotechnical engineering for ground improvement. This study presents a novel analytical method for estimating the bearing capacity of a group of stone columns (GSCs) using the imaginary retaining wall (IRW) theory and establishing equilibrium between the passive and active forces on two sides of the IRW. An equation for calculating the bearing capacity of GSCs is then derived. The individual column model is transformed into an equivalent area model through equivalent characteristics based on the weighted average of SCs and the surrounding soil. The proposed method is validated using laboratory, field, and numerical data, and also against another analytical method from the literature. Parametric studies and sensitivity analyses are conducted using ANOVA to explore the influence of contributing parameters on the predictions of the proposed method. It is observed that the friction angle and cohesion of the native soil surrounding the SCs are the most influential parameters, while the unit weight of native soil and SC aggregates has the least effect. Design tables for estimation of the bearing capacity of GSCs are provided, which are valuable for practical applications.