Effects of cyclic loading on soil arching within pile-supported embankment with artificial crust: A coupled DEM-FDM approach

Abstract

This study endeavors to investigate the evolution of soil arching within pile-supported embankments featuring artificial crusts under cyclic loading. A quasi-three-dimensional (quasi-3D) model was formulated utilizing the Discrete Element-Finite Difference coupled method (DEM-FDM) and validated by in-situ vibration tests. The mechanism underlying the soil arching weakening due to cyclic loading was elucidated, and the impacts of artificial crust moduli and thicknesses on soil arching were consolidated. The findings demonstrate that the equal settlement section moves upwards, and the lower limit of the settlement trough resulting from cyclic loading extends downward with an escalation in axle load, but these remain relatively consistent as the loading velocity increases. Additionally, the transmission of dynamic stress from the pavement surface to the outer surface of the arch approximately adheres to the Boussinesq formula, whereas the stress propagation from the outer surface to the top of the pile cap conforms to the prescribed dynamic pile-soil stress ratio. Furthermore, increasing the thickness and the elastic modulus of the artificial crust contributes to diminished pile-soil differential settlement, alteration in the pile-soil stress ratio, lowered susceptibility of artificial crust deflection to cyclic loading, reduced anisotropy coefficient, and a counterclockwise rotation in the primary direction of the normal contact force exerted on particles within the arch region.