中文摘要：

块石凸体的咬合作用是保证滑面贯通型坡体稳定的核心屏障，但其强度机理和解锁模式还不清晰。为此，以岩石力学为基础，通过合理建模分析了咬合失稳模式。继而，借助古典摩擦定律和极限分析理论，分别从接触和能量角度阐明了凸体在滑跃和剪断两类不同模式下解锁的条件和机理，解析了不同荷载环境下凸体咬合强度的表达。最后，算例分析表明：1）下滑力丁与上覆荷载P的绝对值及相对值决定了咬合凸体的稳定状态和破坏模式。当T／P较大且大于临界值ξ后咬合凸体滑跃解锁，反之当T/P较小但，却够大时凸体剪断解锁，否则保持稳定；2）滑跃解锁是凸体几何形状和荷载环境满足条件下咬合面滑动摩擦的结果，而剪断解锁则是外力功沿潜在破坏面耗散的过程；3）滑面凸体咬合强度是不同荷载环境下凸体以不同模式失稳的临界力学条件的综合反映。

英文摘要：

The interlocked action of stone asperity on transfixion sliding surface plays an important role in rock slope stability, but its mechanism and strength is not studied clearly. Here, based on rock mechanics and reasonable assumption, the stone unlocking models are analyzed first. Then taken classical friction law and upper bound theorem as measures, both the mechanisms and the condiations of two unlock models of Leap-slide and Shear-break are studied from the view of friction and energy respectively. Moreover, the shear strengths of interlocked stone under different loads are also given. At last, an example is given and the result shows that： 1） the stones＇ stability and unlock model are determined by the relative value of sliding force T with normal load P and their absolute value. When T/P is bigger than the critical value ξ, the stones will unlock by Leap-slide. On the contrary, when T/P is small but T is big enough, the stone will be sheared break. Otherwise, the stone will keep interlocking; 2） Leap-slide is the result of sliding friction of occlusal surface, and Shear-break is the process of energy dissipation of external work on potential failure surface; 3） the interlock strength is the reflection of critical mechanism coditions when stone asperities unlock under different external loads.