Laboratory and Three-Dimensional Numerical Modeling of Laterally Loaded Pile Groups in Sandy Soils

Abstract

The lateral response of piles embedded in soil is typically analyzed using the Winkler nonlinear springs method. The predictions of “load–displacement” response of the pile group are needed for a safe and economical design. In this method, the soil–pile interaction is modeled by nonlinear p-y curves in a way that the single pile p-y curve is modified using a p-multiplier for each row of piles in the group. The average p-multiplier is called the group reduction factor. Most research has focused on the behavior of laterally loaded single piles, though piles are most frequently used in groups. The present study was conducted to investigate the effects of various parameters, such as the pile spacing, different layouts, and the lateral load angle change as a new parameter, on the lateral response of piles, group efficiency, and p-multiplier factor in the group. Soil is modeled as an elastic–perfectly plastic material using the modified Mohr–Coulomb constitutive model. In addition, the Abaqus 3D model is validated using load–displacement results from laboratory tests of laterally loaded piles embedded in sand. The p-multiplier factor calculated from this study is well comparable with those of the full-scale tests on pile groups. However, based on the results, the calculated values of the p-multiplier factor at S/D = 3 (obtained from interpolation the values of group reduction factor at S/D= 2.5 and S/D = 3.5) are close to those recommended by the AASHTO, especially for 3 × 3 pile group.