Factors Influencing the Seismic Collapse of Stratified Steep Cliffs Based on Analytic Hierarchy Process (AHP)

Rockfalls from stratified unstable rock masses on cliffs present a significant geological hazard. This study investigates their seismic failure mechanisms and quantifies the influence of key controlling factors through an integrated approach of shaking table tests and UDEC numerical simulations. The introduction of a displacement angle precisely defined failure initiation, with tests revealing that the collapse angle exhibited a strong positive correlation with block size. Numerical simulations on seven factors showed that the collapse displacement angle ranged from 9° to 21°, primarily controlled by joint spacing. The Analytic Hierarchy Process (AHP) quantified the factor priorities, identifying the degree of rock mass fragmentation as the most influential factor with a weight of 0.278, followed by seismic amplitude (0.222) and cliff slope angle (0.167). The results provide a quantitative basis for designing early-warning systems using displacement angle thresholds and prioritize targeted mitigation strategies for the most critical factors in seismic-prone regions.