Geological characteristics, disaster mechanisms and stability analysis methods of rock slope toppling

Toppling failure is a typical type of disaster associated with rock slopes. The deformation behaviors and mechanisms underlying the evolution of rock slope toppling are complex, influenced by adverse geological conditions and external loads. Investigating the deformation characteristics, failure modes, and disaster mechanisms of rock slope toppling, as well as proposing methods for stability evolution, are urgent issues in slope engineering. Approximately 220 cases of toppling slopes in China have been collected, and the regional distribution of these cases is presented. The relationships between toppling failure and several key factors, such as slope height, slope angle, terrain obliquity, and lithology, are thoroughly analyzed. Building on existing classification methods for rock slope toppling, a four-level classification method is proposed based on the tendency relationship between the dominant discontinuity and the slope, the dominant or subordinate status of toppling deformation, the deformation characteristics of the toppling body, and the combination of toppling strata. The deformation behaviors and failure mechanisms of typical toppling types, including block toppling, flexural toppling, and composite toppling, are revealed through a combination of physical model tests and numerical simulations. Systematic presentations of stability analysis approaches, including the G&B method, equivalent continuum method, Liu method, cantilever beam method, and composite analysis method, are provided, along with discussions on their limitations and evolving trends. This research is expected to serve as an important reference for theoretical studies and engineering practices related to rock slope toppling.