Cyclic Lateral Response of Large-Diameter Monopiles in Soft Clays Using Bounding Surface-Based Analytical p-y Curves

Abstract

The p-y curve method provides a relatively simple and efficient means for analyzing the cyclic response of horizontally loaded piles. This study proposes a p-y spring element based on a bounding surface p-y model, which can be readily implemented in Abaqus software using the user-defined element (UEL) interface. The performance of these p-y spring elements is validated by simulating field tests of laterally loaded piles documented in the literature. The developed spring element effectively replicates the nonlinear hysteresis, displacement accumulation, and stiffness degradation observed in soft clay. Subsequently, a finite element model of a large-diameter monopile is established using the proposed spring element. A comprehensive numerical investigation is conducted to explore both the monotonic and cyclic responses of large-diameter monopiles in soft clays. The results are presented and discussed in terms of pile head load–displacement curves, the evolution of rotation angles at the mud surface, and cyclic p-y curves. Additionally, empirical formulas are proposed to predict the evolution of cumulative rotation angles and peak bending moments under both one-way and two-way cyclic loading conditions. The results provide valuable insights into the mechanism of pile–soil interaction under lateral cyclic loading.