Bearing Capacity of Soft Clays Improved by Stone Columns: A Parametric Analysis

Abstract

A detailed numerical analysis has been performed on a unit cell stone column by varying parameters such as shear strength of clay, angle of internal friction of the column material, slenderness ratio (L/d) of the column, area replacement ratio, and the modular ratio, Poisson's ratio of clay and column material. A parametric study is conducted for floating stone column by using the finite element package PLAXIS. A drained analysis was performed using Mohr–Coulomb criterion for both the materials. Validation was done by taking experimental data for a single unit cell stone column. From the analysis, it is observed that the bearing stress increases with increase in the aspect ratio (L/d) up to a particular range beyond which there is negligible change in the bearing capacity. Bulging is the main cause of failure of a single stone column when loaded alone. An increase in the area ratio caused an increase in the bearing value of the stone column-reinforced soil due to higher relative stiffness. The most influential parameters for the design of stone column-reinforced soil are the angle of internal friction of the column material and area replacement ratio whereas the cohesion of surrounding material, slenderness ratio and Poisson's ratio contribute to a lesser magnitude.