Energy-based analysis of seismic failure mechanism of a rock slope with discontinuities using Hilbert-Huang transform and marginal spectrum in the time-frequency domain

Abstract

An energy-based identification method is proposed to investigate the seismic failure mechanism of landslides with discontinuities. The proposed method was verified by using shaking table tests on a rock slope with discontinuous structural planes. The results show that it is feasible to analyze the seismic failure mechanism of the slope by using Hilbert-Huang transform (HHT) and marginal spectrum based on seismic Hilbert energy. Earthquake energy mainly concentrating in the low-frequency components (15–17 Hz) and high-frequency components (20–40 Hz), in Hilbert energy spectrum and the marginal spectrum, respectively, suggests that they can identify the overall and local dynamic response of the slope, respectively, in combination with the Fourier spectrum analysis. In addition, the analyses of marginal spectrum can better clarify the slope dynamic damage process from the energy-based perspective, including no seismic damage stage, local damage stage, and sliding failure stage. The difference of seismic Hilbert energy between slip mass and sliding body causes their different seismic responses. The seismic failure mechanism of the landslide is identified from the energy-based perspective: the seismic Hilbert energy in 20–40 Hz mainly induces the local damage of the slope above the topmost bedding structural plane, and local failure develops first at the platform, under 0.297 g; the surface slope gradually forms a sliding body with the accumulation of local damage, and the seismic Hilbert energy in 15–17 Hz further promotes the landslide subject to 0.446 g.