Pile supported geogrid-reinforced embankment are widely used to treat soft soil. This paper proposes a novel method for reinforcing foundations using non-foamed polyurethane-bonded gravel (NPBG) porous piles. Through triaxial compression tests, the mechanical properties and strength parameters, such as strength and stiffness, of the polyurethane-bonded gravel material are determined. Finite element numerical simulations are then employed to investigate the bearing characteristics of NPBG porous pile under embankment loads. The experimental results indicate that, under the same confining pressure, the strength and stiffness of the NPBG material are significantly higher than those of plain gravel material, while still retaining large pore characteristics. Increasing the polyurethane content enhances the strength and stiffness of the porous material, but the improvement diminishes as the confining pressure increases. A systematic comparative analysis was conducted on the bearing characteristics of NPBG porous pile versus concrete pile, cement-mixed pile, and gravel pile under embankment in terms of load sharing ratio and settlement deformation. The permeability coefficient and modulus of the pile significantly influence the dissipation rate of excess pore water pressure in the foundation soil. The NPBGP pile exhibited the fastest consolidation speed, effectively controlling total settlement and reducing the proportion of post-construction settlement of the embankment. Compared to concrete pile and cement-mixed pile, the NPBG porous pile has a lower uniform settlement surface height in embankment, making it suitable for low-height embankment accelerated construction projects.

The existing earthquake damage investigations indicate that the lateral spreading of site is more likely to occur in inclined liquefiable site under earthquake, therefore the way of foundation reinforcement is often adopted to reduce the lateral spreading phenomenon of inclined liquefiable site. In order to study the reinforcement principle of inclined liquefiable site by the two reinforcement methods of concrete pile and gravel pile, based on the verified numerical model of free field model, the model of concrete pile reinforcement and crushed rock pile reinforcement was established, the dynamic response and reinforcement effect of two different reinforcement methods in inclined liquefiable site were analyzed, and the effects of buried depth and pile diameter on the earthquake dynamic response and the effects of different reinforcement models are discussed. It is found that the concrete pile has a better reinforcement effect on inclined liquefiable site than gravel pile under the same buried depth and pile diameter. When the concrete pile is adopted to reinforce the inclined liquefiable site, the reinforcement effect is better when the concrete pile are embedded in dense sand layer at a certain depth; When adopting the gravel pile to reinforce inclined liquefiable sites, the effect is better when only clay and loose sand layer are reinforced, moreover, increasing the diameter of gravel piles greatly improves the reinforcement effect of inclined liquefiable sites. The pile group reinforcement model can greatly reduce the lateral displacement of site soil compared with the single pile reinforcement model.