中文摘要：

危岩是三峡库区典型的地质灾害类型之一,主要分为坠落式危岩和倾倒式危岩两种失稳形式,危岩主控结构面受荷断裂扩展是其发育成灾的关键核心。将危岩主控结构面类比为宏观裂纹,运用扩展有限元方法（XFEM）,求解结构面扩展过程的移动非连续问题,探索在荷载作用下危岩主控结构面的断裂扩展行为,以重庆万州太白岩危岩为例,考虑岩石的抗拉强度、主控结构面的几何位置与倾角对危岩的变形破坏模式与稳定性的影响。结果表明,随着岩石抗拉强度的降低,危岩的稳定性程度降低;随着主控结构面倾角的减小,危岩的稳定性程度提高,同时结构面开裂路径也明显改变;危岩体两种失稳模式的破坏机制都为拉剪机制,相对于倾倒式危岩,同等条件下坠落式危岩的稳定性更差。

英文摘要：

The perilous rock is one of the typical disasters in the Three Gorges reservoir region; it can be classified as two types in views of perilous mode, i.e. falling perilous rock and toppling perilous rock. Crack propagation of control joint of perilous rock under loads is the key process in failure of perilous rock. In this paper taking the control joint in perilous rock as one crevice in a sample, to solve the moving discontinuities of joint propagation by extended element method and explore the crack propagation behavior of control joint of perilous rock under loads. The Taibaiyan cliff at Wanzhou is a representative case of massive perilous rocks in the area. Using this cliffas an example, the effect of joint location, obliquity and rock tensile strength on the failure mode and magnitude of safety factor were investigated. The results demonstrate that with the decreases of rock tensile strength, the perilous rock stability decreases; and with the decreases of control joint obliquity, the perilous rock stability increases. The destructive mechanism of two unstable modes for perilous rock is tension-shear. As opposed to toppling perilous rock, under the same conditions, the stability of falling perilous rock is even worse.