Effect of Soil Permeability of Liquefiable Ground on Pile Group Behavior: 3D Numerical Analysis

Soil-pile interaction in a liquefied ground is one of the most complex problems in geotechnical earthquake engineering. In this research, a series of numerical analyses was performed to investigate the behavior of a pile group in a liquefied ground using a three-dimensional finite element software. The investigation highlighted the effect of soil permeability and density in liquefiable soil-pile interaction. A harmonic sinusoidal loading was applied to each model. Discussions cover pile deformation, bending moment, and excess pore water pressure. The results show that increasing the permeability of conventional soil from 5 × 10−4 m/s to 7 × 10−4 m/s noticeably increased the maximum pile deformation and bending moment. The liquefaction triggering and dissipation of excess pore water pressure also occurred much later in the denser ground with lower permeability. However, replacing the loose sand with lightweight aggregate, permeability of 0.01 m/s, prevents liquefaction triggering, and halves the maximum bending moment of the piles.