Effect of Cap Stiffness and Soil Dilatancy in Pile Groups Subjected To Lateral Loads

Abstract

This paper explores the effect of cap stiffness and soil dilation on the structural response of pile groups subjected to lateral increasing monotonic loads. For such scope, a finite element-based model for studying pile configurations of 3x3 to 3x7 in homogeneous sand deposits is proposed. The model employs solid elements with twenty nodes to represent the soil and pile domains, while zero-thickness interface elements are used to model the contact state at the soil-pile interface. The adequacy of the model is firstly validated with experimental data from literature and then the associated parametric studies involving the two aforementioned aspects are performed. For the studied examples, the obtained results indicate that the reduction of the cap stiffness substantially increases the lateral displacement of the system. This increment under ultimate loads can be as high as three times the lateral displacement of the original system with a rigid cap. Finally, soil dilation did not significantly affect the pile group response as the soil mass seems to be restricted by the surrounding piles.