暴雨是诱发震后岩质滑坡失稳的最重要因素之一,与土质滑坡不同,其相关作用机理还不清楚。在基于对震后受损岩体特征的科学认识前提下,从岩石断裂力学的角度出发,分析了坡体裂缝扩展、降雨入渗和滑面形成机制。继而以极限分析的上限定理为基础,从能量的角度定量研究了裂缝水对岩质坡体稳定性的影响。最后,通过算例表明:震后受损岩坡的裂缝存在一个可在裂缝水作用下自行扩展、贯通软弱夹层的临界深度,同时也存在一个决定滑坡体稳定与否的软弱夹层渗水区域极限长度,即裂缝的扩展贯通和滑面的渗水软化是震后暴雨型岩质滑坡的启动的根本动力。
Among the triggering factors of post-earthquake rock landslide,the rainfall water plays a most important role.However,different from that of soil slope,the mechanism of its effect on rock landslide failure is not clear.From the view of fracture mechanics and based on the characters of post-earthquake rock,the mechanism of crack propagation,the way of water infiltration and the development process of sliding face are studied.By using the upper bound theorem,the influence of fissure water on the stability of rock slope is quantitatively studied.Finally,an example is given to prove the theory.The results show that the propagation and coalescence of fissures and the softening of sliding face are the main reason for the failure of post-earthquake rock landslide under rainfall.