Performance analysis of a jacked-in single pile and pile group in saturated clay ground

When a pile is installed into saturated clay ground, the “setup” effect may occur due to ground consolidation, which changes pile performance. Although this phenomenon has been observed both in the field and laboratory, its numerical simulation is still challenging. In this work, pile installation effects on the behaviors of jacked-in piles were investigated through three simulation techniques by a three-dimensional finite element analysis program, PLAXIS 3D. A constitutive model called the soft soil creep model was used to describe the soil behavior based on soil parameters obtained from laboratory tests. The behaviors of single piles were first investigated with or without the consolidation process after pile installation to evaluate the pile setup effect. Then, a pile group comprising 4 piles was analyzed using the consolidation process to verify the applicability of the three simulation techniques. The calculated results were compared with the corresponding experimental results. The calculated results using three techniques generally agreed well with the experimental results in terms of initial stiffness and pile shaft resistance. Both the measured and calculated results indicate that ground consolidation caused by pile installation significantly increases the pile bearing capacity and especially, the pile shaft resistance. Therefore, the pile setup effect can be reasonably simulated by the three proposed techniques.