• • Optimized iron tailings sand-bentonite mixture: permeability coefficient k decreases exponentially with bentonite content (CB), from 10^-4 cm/s at CB=0% to 10^-8 cm/s at CB=9%, meeting the engineering standard k≤10^-7 cm/s; beyond 9%, marginal benefit diminishes, guiding cost-effective material selection.
• • Three-dimensional anti-seepage system with 'pre-embedded pipe + expansion bolt' technique: enhances structural integrity at critical nodes, reducing leakage risk; enables performance-based design over compliance-based design, improving long-term reliability.
• • Environmental remediation efficacy: after implementation, heavy metal concentrations in farmland soil decreased by 11.14%–72.41%, all below risk screening values; Fe and Cr interception rates reached 97.17% and 96.76%, respectively, demonstrating effective containment of contaminant migration.
• • Integrated design-construction-evaluation framework: achieved 2.78% increase in tailings resource utilization and 4.71% reduction in engineering cost, while reducing Nemerow index from 2.39 (moderate) to 0.62 (none) and potential ecological risk index from 288.50 (moderate) to 148.73 (slight), validating the approach's technical and economic viability.