PFC-FLAC3D Coupled Modeling on Rammed Stone Columns

A three-dimensional Particle Flow Code (PFC)-3D and Fast Lagrangian Analysis in the Continua (FLAC3D) coupled numerical model is presented in this study to investigate the bearing capacities of rammed stone columns (RSCs) taking into account the installation effects. The accuracy of the coupled model is verified against model test data. Parametric studies are conducted to explore the influence of key parameters on the bearing behaviors of the RSCs. The results indicate that the RSCs exhibit semirigid pile characteristics with an optimal initial hole depth of 5 d and a column length of 6.9 d. A higher soil strength around the column effectively restrains its lateral expansion. The puncture failure often occurs when the initial hole depth is <5 d, while bulging failure is observed when that exceeds this value. The failure zone in the surrounding soil can be categorized into a truncated cone and a bulging deformation zone. The angle between the shear slip surface and the column remains constant, with its magnitudes ranging from 18° to 20°.