Comparative Finite Element Study of Single and Group Piles Adjacent to Slopes Under Lateral Cyclic Loading
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Abstract
This study investigates the performance of a single pile and a (2×2) pile group located near saturated clayey slope under cyclic lateral loading using Finite Element Analysis (FEA). The simulations were conducted using Plaxis 3D with the Hardening Soil Model (HSM), which allows for a more accurate representation of soil behavior, especially in cyclic loading conditions. The model considered clayey soils with parameters derived from the official geotechnical report prepared by the Consulting Engineering Bureau (CEB) Laboratories of the University of Baghdad's College of Engineering. Both the single pile and pile group were placed at a distance of (4D) from an (8m) high slope with a (1:4) gradient. The loading conditions included static vertical loads and cyclic lateral loads. The most important results reached, pile groups reduced lateral displacement by 30-50% versus single piles, which suffered 20-40% greater displacement near slopes due to uneven soil support. One-way cyclic loading caused larger than two-way cyclic load permanent displacements, while two-way loading increased fatigue risks, with both degrading clay strength by up to 50%. Peak bending moments occurred at pile heads and slope crests, but group piles lowered these stresses by 30%.
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