Numerical investigation on the seismically induced progressive failure of the 2017 Xinmo landslide in China

The Xinmo landslide, a catastrophic event that claimed 10 lives and left 73 people missing, occurred in an active tectonic zone on the eastern margin of the Tibetan Plateau. Although it is widely recognized that multiple earthquakes in the region have historically inflicted severe damage on the slope, there has been a lack of quantitative investigation into the slope's deformation and damage processes under repeated seismic events. In this study, we examined the response, deformation, and fracture processes of the Xinmo slope under multiple earthquakes through a series of numerical simulations. Our findings reveal that repeated earthquakes cause an amplification of slope acceleration, strain, and stress amplitudes, leading to the progressive accumulation of deformation and cracking in slopes at increasingly faster rates. The observed stress amplification in the phyllite layer, attributed to incompatible deformation, significantly contributes to the intensive development of seismic cracks. Additionally, the incremental damage and deformation caused by each earthquake are strongly influenced by pre-existing damage. The accumulation of earthquake-induced residual stresses in locked segment is a major factor in accelerating its buckling deformation. This study emphasizes the importance of incorporating earthquake-induced cumulative damage into landslide stability and hazard assessments.