Study on development characteristics and failure modes of reservoir bank landslides in lower Jinsha River

The lower Jinsha River area is characterized by intricate engineering geological conditions and frequent landslide hazards, which pose a severe threat to the safe operation of cascade hydropower stations and public safety.Based on field investigations and systematic statistical analysis of 353 landslides in the area, the distribution characteristics and failure modes of these hazards were studied.The results indicated that landslide development was jointly controlled by lithology, bank slope structure and geological structure three major factors.Lithologically, clastic rock formations were the most extensive landslide type, covering 45.4% of the study area, whereas carbonate rock formations displayed the highest landslide density, and the landslide area of corresponding rock groups accounts for 7.5%.Structurally, layered bank slopes were the most susceptible to failure, with consequent bedding landslides showing the leading proportions in quantity, volume proportion, and distribution density.Tectonically, more than 55% of the landslides were concentrated within a 2 km of the main fault zones.Based on the coupling relationship among stratigraphic lithology, slope structure, and geological structure, a classification system for landslide failure patterns dominated by "formation-controlled" and "structure-controlled" was put forward.The results can provide a reference for landslide identification, risk evaluation, and strategies for disaster prevention and mitigation in the lower Jinsha River area.