Damage evolution of the bedding rock landslide and debris landslide under earthquakes in the Three-rivers Basin

The geological structure of the Three-rivers Basin is complex, with active tectonic movements and frequent earthquakes, resulting in fragile geological circumstances, frequent geo-hazard incidents, and the emergence of significant hazard cascades. Multiple earthquakes lead to frequent landslide disasters. Bedding rock and debris landslides are common disasters that threaten the Three-rivers Basin's infrastructure construction. In this study, we took the “Xiaguiwa” landslide as an example and established shaking table models of bedding rock and debris slopes. The Arias intensity, improved marginal spectrum multi-peak slope damage identification based on Hilbert-Huang transform (HHT) and Standard spectral ratio (SSR) were used to analyze the seismic damage evolution of the model slope and the influence of the accumulation layer on seismic energy transfer. The results show that seismic tension leads to damage in the top accumulation layer of the debris slope. The damage to the bedding rock slope first appeared at 1/4 elevation of the slope surface due to buckling. Then, shear deformation occurs at the trailing edge and expands downward along the structural plane. This process co-occurs with the depression at 1/2 elevation of the slope. The accumulation layer has different effects on the seismic energy of different elevations, and its influence on the seismic energy of low frequency (<10 Hz) and high frequency (>40 Hz) is more significant. The damage evolution of bedding rock slopes can be segmented into four stages: (1) slight subsidence of rock layers stage, (2) rock bending and trailing edge cracking stage, (3) slope waist depression and uplift surface fracture stage, and (4) shear-fracturing and the low-position shear out stage; That of debris slopes can be segmented into three stages: (1) accumulation layer peeling stage, (2) accumulation layer cracking stage and (3) overall collapse stage.