危岩崩塌是一种常见且破坏性极大的地质灾害，而地震是导致危岩崩塌的主要因素之一。数值模拟是研究危岩崩塌的重要手段。以概念危岩为例，运用非连续变形分析（DDA）法研究了地震荷载对危岩体崩塌块体运动特性的影响。对无地震荷载和3种不同地震荷载输入方式的4种工况进行了模拟。研究结果表明：地震荷载对危岩崩塌破坏有促进作用，不同的地震荷载输入方式对崩塌块体的运动特性有着显著的差异。从算例来看，竖向地震动对崩塌块体运动距离的影响程度甚至比水平地震动对其的影响程度更大，这与人们的传统观念不同，在今后的地震危岩崩塌防治措施设计中，应对竖向地震荷载给予足够的重视。

As is well-known, rock-fall is one of the most common geo-hazards and always causes serious damage to both lives and properties. There are many triggering factors that give rise to the occurrence of rock-fall disaster and earthquake is one of the main triggers, while often leading to a greater loss than other factors. As one of the methods to carry out researches of rock-fall, numerical simulation plays an important role in the study of movement characteristics. A conceptual rock-fall model with four cases, one without seismic loading and three with different seismic loading input modes, is used to simulate the effect of seismic loadings on the mobility characteristics by discontinuous deformation analysis (DDA). The simulation results show that the seismic loading prompts the collapse of potential rock-fall and different seismic loading input modes have different significant influences on the mobility characteristics of the collapse block. Another important conclusion is the vertical component of seismic loading has more significant influence on the movement distance of collapse block than the horizontal component, which differs from the traditional knowledge about the earthquake-induced rock-fall. Thus the vertical seismic loading should be given enough attention in the future prevention design of earthquake-induced rock-fall.