Two-Dimensional Limit Equilibrium Analysis of Tailings Dam Stability under Rainfall-Seismic Coupling
Abstract
: Rainfall infiltration and earthquake loading are two important external factors affecting the stability of tailings dams, and their sequential action may significantly reduce the stability reserve of a dam slope. In this study, a representative cross-section of a valley-type tailings dam was established in GeoStudio, and SEEP/W-SLOPE/W coupling was used to evaluate the dam under initial, rainfall, earthquake and rainfall-seismic coupled conditions. The Morgenstern-Price method was selected because it satisfies both force and moment equilibrium and is applicable to non-circular slip surfaces. The results show that the initial factor of safety is 1.486. Under rainfall, the factor of safety decreases with increasing rainfall intensity, reaching 1.453 for the local daily maximum rainfall of 151.4 mm/d. Under earthquake loading, the safety factor decreases from 1.423 to 1.317 as the horizontal seismic coefficient increases from 0.017 to 0.10. The coupled condition is the most unfavorable case, with the factor of safety decreasing to 1.273, but still higher than the specification threshold of 1.15. The analysis clarifies the evolution of pore-water pressure, the decrease in stability reserve and the shallow migration of the critical slip surface under coupled rainfall and seismic loading.