Revealing the characteristics and type of chair-shaped landslides considering the reservoir water effect in the Three Gorges Reservoir Area, China

Widely distributed chair-shaped landslides in the Three Gorges Reservoir Area (TGRA) have caused significant economic damage and loss of life globally. Present studies have an over-reliance on individual case reviews, resulting in circumscribed conclusions. Furthermore, the classification criteria for chair-shaped landslides diverge across various researchers. This manuscript, therefore, systematically studies 160 chair-shaped landslides, providing a comprehensive analysis of their unique characteristics. The study then pivots to focus on a prototypical instance, the Jiuxianping landslide, to probe the landslide’s stability across diverse conditions, thereby discussing the type of chair-shaped landslide. The outcomes suggest that the type of chair-shaped landslides (seepage-induced or buoyancy-induced landslides) may interconvert due to varying parameters such as dip angle (β), permeability coefficient (K), reservoir water fluctuation rate (V), and the fluctuation range of the reservoir (S’). These parameters, which differ for each chair-shaped landslide, lead to varying findings among different scholars.