DEM Numerical Comparison of Static and Cyclic Shear Performance between OSCs and GESCs

ABSTRACT The geosynthetics can improve the shear performance of ordinary stone columns (OSCs) to resist the lateral force caused by embankment surcharge and seismic loads. The discrete element method (DEM) is employed to analyze and compare the static and cyclic shear performance of OSCs and geosynthetic‐encased stone columns (GESCs). The vertical and shear deformation, deformation of encasement, contact force distribution, porosity, coordination number, and radial stress coefficient are investigated. Furthermore, the effect of five critical factors on the cyclic behavior of GESC is explored. Numerical results show that GESC installation substantially enhances the shear resistance of sand compared to OSC. The column‐soil systems exhibit rapid stabilization during the initial loading cycles. The vertical strain, shear stress, porosity change, and average coordination number variation of GESC or OSC under cyclic conditions are larger than under static conditions. The maximum vertical strain in GESC demonstrates a positive correlation with loading amplitude ( s m ) and normal stress ( σ n ), while inversely correlating with loading frequency ( f ), encasement length‐to‐column length ratio ( L e / L c ), and column diameter ( D ). High f or s m amplifies the shear stress within GESC systems.