Numerical Modeling on Behavior of Annular Stone Column in Layered Soils

In the past, many studies on the improvement of soft soils to increase the load-carrying capacity and reduce settlements found that ordinary and encased stone columns have been increasingly used. In this present work, an annular-structured stone column is introduced into the ground to study the behavior of the column in layered soils. Two types of layering systems, i.e., soft clay overlying stiff clay and vice versa, are considered for the present study. To know the performance of an annular stone column, numerical models were carried out by taking the internal and external diameters of 40 mm and 80 mm, respectively, with geo-reinforcement and varying the thickness of the top layer as well as the bottom layer. To know the load-carrying capacity of an annular stone column by giving a prescribed displacement, a detailed parametric study was carried out using the finite element-based software Plaxis 3D. For the soil and stone columns in the numerical analysis, the elastic-perfectly plastic Mohr-–Coulomb failure criterion with drained and un-drained conditions was used.