Numerical stability analysis of piled embankments reinforced with ground beams

Rigid piles are extensively used to support high-speed railway embankments resting on soft ground, and ground beams are structural elements at ground level to connect adjacent pile caps to improve the stability of pile-supported embankments. In this study, a validated three-dimensional numerical model of piled embankment was developed based on a well-documented centrifuge test, where the Mohr-Coulomb tension crack model was adopted for capturing the brittle failure behavior of concrete piles. The results showed that concrete piles are subject to a serious bending failure within the clay layer when the overlying embankment collapses. By introducing the ground beams in conjunction with rigid piles, the resultant displacement of the improved area was markedly decreased and the pile failure mode was changed. The combination of concrete piles and ground beams results in a synergistic effect. According to the mechanical response of individual piles, the foundation soil was divided into the extension-bending, bending, bending-compression, and compression zones to elucidate the reinforcement mechanism related to ground beams. A proper arrangement of ground beams was ultimately obtained based on the localized slip resistance performance of the improved ground. Overall, this research contributes to the knowledge of piled embankment performance evaluation and may further extend the practical application of ground beams.