Model tests study of multi-layer geosynthetic-reinforced pile-supported embankments and evaluation of analytical design models

Single and multi-layer geosynthetic-reinforced pile-supported (GRPS) embankments are widely used in practice. Various analytical design models were developed to analyze GRPS embankments. However, engineering experience has shown that the performance of multi-layer GRPS embankments differs from that of single-layer GRPS embankments. The applicability of these analytical design models based on different assumptions has not been fully validated. This paper conducted the physical model test on multi-layer GRPS embankments to clarify their macroscopic mechanical properties. The performance of eight analytical design models under different relative embankment heights was assessed based on the results of the physical model test, using arching efficiency and reinforcement strain as comparison parameters. The results from the physical model test indicated that increasing the number of reinforcement layers in GRPS embankments can more significantly enhance their performance in terms of load transfer and deformation control, as compared to increasing the reinforcement strength of single-layer GRPS embankments. Unlike the membrane behavior exhibited by single-layer reinforcement, the mechanism of multi-layer reinforcement is closer to beam behavior due to the interlock between the reinforcements and the granular fill. Additionally, there is a positive correlation between the prediction accuracy of analytical design models and the relative embankment height, both in predicting the arching efficiency and the reinforcement strain. The accuracy of selected analytical design models in predicting reinforcement strain is found to be weaker in comparison to their predictive capabilities for arching efficiency. Finally, the EBGEO model has good performance, which is grounded in limit equilibrium theory, considers subsoil bearing capacity, and assumes a triangular distribution of the overburden load on the reinforcement.