Modeling the Effect of Drainage and Reinforcement on the Stability of Open Pit Coal Slopes

Slope stability is of critical importance for both the economic sustainability of open-pit mining operations and occupational safety. Similarly, in highway engineering, the stability of cut and fill slopes is vital for ensuring transportation safety and the continuous functionality of infrastructure networks. The primary factors threatening this stability include weak geological strata, structural discontinuities, and fluctuations in the groundwater level. The study discussed herein investigates the efficacy of various mitigation scenarios—namely, drainage to lower the groundwater level and reinforcement using mortar-filled anchors and soil nails of differing lengths—on a slope model, analyzed through numerical modeling employing the Mohr-Coulomb failure criterion and limit equilibrium methods (Simplified Bishop and Janbu). A key finding of this research extends beyond merely calculating factors of safety; it underscores the paramount importance of determining the economically optimal solution through cost-effectiveness analysis. For instance, the results demonstrated that while 25-meter soil nails increased the factor of safety, the marginal gain was negligible compared to 15-meter nails, suggesting the latter may represent a more rational and sustainable engineering choice. Consequently, this study serves as a valuable reference for developing technically sound and economically optimal engineering solutions for slope stability challenges encountered in both mining and civil infrastructure projects.