Numerical investigation of cyclic load effects on geogrid-encased stone columns using a 3D coupled method

Abstract

Geosynthetic-encased stone columns (GESCs) represent an efficient and cost-effective solution for enhancing weak soil foundations. The deformation and load-bearing mechanisms of GESC-improved foundations under traffic flow are complicated due to substantial particle movements and soil disruption. A three-dimensional discrete-continuum coupled numerical model was proposed in this study to investigate the cyclic behavior of GESC-improved soft soil. The reliability and accuracy of proposed model was validated through experimental data. The effect of cyclic loads, bearing stratum, and geogrid encasement was investigated. Microscopic investigation of particle movement, contact force distribution, and stress transfer mechanism was performed. The vertical loads transferred from the column to the surrounding soil with the interaction effect between the aggregates and the soil. The stress concentration ratio decreased with the increase in depth. The geogrid encasement facilitated the load transfer process by effectively confining the particles and enhancing the column stiffness. The particles in the low segment of floating column exhibited large downward displacements and punching deformation. The geogrid encasement and cyclic loads contributed to enhanced compaction and coordination number of the aggregates.