Study of the Behavior of Floating Stone Columns in Soft Clay Formations Using Numerical Modeling

Stone columns have been increasingly acknowledged as one of the viable foundation techniques in soft ground conditions. The concept behind this option is to enhance soft soils by insertion of special elements stiffer than the original soil. The stiffness of the improved ground depends on the geometry of the stone columns in addition to the relative stiffness between the original soft soil and the installed elements. Back analysis of case histories is always a successful and reliable approach in studying the in situ behavior of different ground improvement methods. In this paper, a well instrumented case study of floating stone columns installed in the Bothkennar soft clay formation is studied using numerical modeling utilizing the finite elements method. Different soil constitutive models are investigated to define the most appropriate one in simulating the actual Bothkennar soft clay behavior. Results of the comparison between the monitored field performance and the estimated behavior from the numerical model using different constitutive models are presented and discussed, while recommendations for the most suitable stress strain model of the studied clay are concluded.