Performance of Field and Numerical Back-Analysis of Floating Stone Columns in Soft Clay Considering the Influence of Dilatancy

Stone column use has gained popularity around the globe as an effective ground improvement technique to improve the load-bearing capacity of soft soils. End-bearing stone columns are commonly used, but occasionally floating stone columns are adopted since they have been proven to achieve the necessary load-carrying capacity and serviceability requirements. However, stone column parameters are often estimated without much basis for simulation and design purposes due to a lack of practical research and real-life case studies in this area. Hence, in order to develop a fundamental understanding of the load-settlement responses of floating stone columns in soft clays, detailed back-analysis was performed in this study. Throughout the back-analysis, all the numerical models were validated by comparing the analysis results with field measurements. This study highlights the existence of some critical interpreted parameters, namely soil cohesion c', friction angle phi', and dilation angle psi', as well as the soil-structure interaction mechanism that influences the load-settlement responses of the floating stone columns. The successful characterization of the stone column materials and the modeling technique of stone columns in finite element analyses show great potential in assessing the real-life performance of floating stone columns in soft clays. (c) 2018 American Society of Civil Engineers.