Seismic response mechanisms of tailings dam under various loading amplitudes and frequencies: Frequency-domain analysis and critical threshold from shaking table model tests

Tailings dams are major man-made hazards of landslides, ranking 18th among international disaster incidents. Earthquakes are one of the primary driving factors that induce tailings dam failures, accounting for 17.1% of the total global tailings dam failure incidents. Therefore, revealing the instability mechanism of tailings dams under seismic loading is of great practical significance. Through shaking table physical model tests, the failure evolution process of the tailings dam under different seismic amplitudes and frequencies was systematically analyzed, with a focus on exploring the dynamic response of pore water pressure, displacement, and acceleration. The correlation mechanism between the seismic response and frequency-domain characteristics of the tailings dam was revealed using the Acceleration Amplification Factor (AAF), Fast Fourier Transform (FFT), and Hilbert-Huang Transform (HHT) methods. The results show that the closeness between the seismic frequency and the natural frequency of the tailings dam significantly affects the intensity of the seismic response, with the most significant under the resonance effect. With the increase of seismic amplitude, the dominant frequency of the tailings dam shows a gradual attenuation trend. However, after the tailings dam is damaged, the dominant frequency gradually increases. This characteristic can be used as a precursor criterion for tailings dam instability. Furthermore, the critical seismic failure threshold was determined, and a prediction model for this threshold was proposed. Combined with the identified seismic failure threshold, the results of this study can provide a theoretical basis and quantitative reference for the seismic stability evaluation, seismic design optimization, and disaster early warning of tailings dams, and have important engineering applications for reducing the risk of tailings dam failure and ensuring the safety of mines and downstream areas.