Simulation of Laterally Impacted Piles in Dry Gravel by Adaptive FEM-SPH Method

The interaction dynamics between soil foundations and embedded piles under impact loading critically influences the performance and behavior of soil-embedded barrier systems. A comprehensive understanding of dynamic pile-soil interaction is vital to developing and optimizing these safety structures. To date, modeling techniques for simulating large soil deformations remain to be developed and/or efficiently demonstrated for this application. In order to bridge this gap, this study presents a computational methodology for simulating dynamic pile-soil interactions under vehicular impacts, capitalizing on the adaptive coupling of the Finite Element Method (FEM) and Smoothed Particle Hydrodynamics (SPH) method. This approach can simulate laterally impacted pile-soil systems at a lower computational cost than SPH alone. The FEM and SPH soil domains interact through an adaptive coupling algorithm, typified by a transition from FEM to SPH based on predefined erosion criteria, while assigning the same soil constitutive model (damaged-based, elasto-viscoplastic) and input parameters (measured or calibrated). The effectiveness and reliability of the proposed technique were ascertained via comparisons with empirical data collected from a unique series of impact tests on steel tube pile-soil systems. These pile-soil systems encompassed various pile shapes, embedment depths, and impact conditions. The results from the adaptive FEM-SPH model showed high conformity with the measured force vs. displacement and energy vs. displacement responses. A comparison with the existing simulation techniques for the pile-soil impact problem showed the adaptive FEM-SPH model’s robustness, adaptability, and accuracy, advancing the understanding of dynamic soil-structure interactions under impact loading. As a result, the adaptive FEM-SPH modeling tool can significantly contribute to evaluating pile-soil system performance, ultimately enhancing motorist safety.