Effects of residual effective stress and particle size distribution on reconsolidation characteristics of granular materials after undrained cyclic shear: a 3D DEM study

抄録

Ground reconsolidation following strong earthquakes can severely damage buildings and infrastructure. However, the nonlinear void ratio–effective stress relationship during reconsolidation remains poorly characterized owing to limitations of laboratory testing. The discrete element method is utilized to examine reconsolidation characteristics in K₀-consolidated granular materials. The results demonstrate that the residual effective stress is the core indicator of the volumetric strain during reconsolidation. Particular focus is given to the post-liquefaction reconsolidation process, which can be divided into two stages: liquefied portion and subsequent solidified portion. The former stage accounts for a substantial proportion of total volumetric strain. For specimens with identical average size, particle size distribution has a major influence on volumetric strain in the liquefied portion while a negligible impact in the solidified portion. This study also finds a higher proportion of floaters in the polydisperse (PD) versus monodisperse (MD) specimen. Furthermore, pore uniformities in both specimens increase during undrained cyclic shear. During the reconsolidation process, pore uniformity rises in the MD specimen while the PD specimen exhibits variable changes.