Investigation of the effect of rigid columns in soil improvement

In this study, the behavior of rigid columns created using ground improvement methods such as stone columns, jet grout, and deep mixing was investigated through laboratory model experiments and numerical analyses. A number of small-scale model experiments were conducted as part of the laboratory studies. The laboratory experiments were carried out in three series. In all experiments, a consolidated soil sample was used under the same pre-consolidation pressure, while tank sizes and rigid column dimensions were varied. In all three series, the rigid column placed at the center of the unit cell was constructed using three different ground improvement methods: stone column, jet grout, and deep mixing. Loading tests were conducted to evaluate the bearing capacities of the rigid columns constructed in the model experiments. As the second phase, numerical analyses of the rigid columns were performed. The numerical analyses were carried out using PLAXIS 2D software, based on the finite element method. Using the same geometric model and soil parameters, stone columns, jet grout columns, and deep mixing columns with different stiffnesses were modeled. As a result, laboratory model experiment results were compared with the numerical analysis outcomes. Based on the results, the influence of significant parameters on the behavior of stone columns, jet grout columns, and deep mixing columns was evaluated, and the findings were presented in detail.