Research on Grouting Pressure of Earth–Rock Dams Reinforced by Polymer Based on Discrete Elements

As a novel seismic reinforcement measure for earth–rock dams, the PFA-reinforced rockfill materials technology lacks comprehensive investigation into both its reinforcement efficacy and the underlying mechanisms. In this study, we establish a fluid–solid coupling model of PFA-reinforced rockfill materials utilizing the matrix discrete element software MatDEM3.24, developed independently by Nanjing University. The model simulates the dynamic process of polymer grouting within the rockfill body and analyzes the impact of slurry diffusion patterns and various grouting pressures on polymer grouting. Our findings reveal that the diffusion of polymer foam in rockfill occurs in three distinct stages, which are characteristic of penetration grouting. Moreover, we observed that grouting pressure had a significant effect on the diffusion range of the slurry, with greater sensitivity noted in the Z direction. Additionally, we observed a decrease in porosity with increasing grouting pressure, and stress augmentation exhibited an approximately linear relationship with grouting pressure, but the stress augmentation in different directions was different. These research outcomes offer valuable insights into the practical implementation and optimization of PFA-reinforced rockfill materials technology, bearing considerable engineering implications.