In the Three Gorges Reservoir Area (TGRA) has frequently occurred a large number of landslides in the stratified rock slopes with typical saw-tooth rock discontinuities since its impoundment in 2003, in which the shear mechanical behaviors of the saw-tooth rock discontinuities have been explored by few scholars. In this study, the macro-meso shear mechanical behaviors of the rock discontinuities with multiscale triangular-shaped asperities under two different lithologic combination types, when subjected to a static constant normal load (CNL), were investigated using experimental and numerical approaches. The hard layer and soft layer are, respectively, limestone and clayey soil taken from the TGRA, and the normal loading rate for the combination of hard layers and the combination of soft–hard layers is 0.5 kN/min and 0.05 kN/min, respectively, while the shear loading rate of the two different lithologic combination types is 0.5 kN/min. The laboratory direct shear tests on the rock discontinuities with different first-order asperity angles, i.e., 30°, 45° and 60°, and the same second-order asperity angle of 45°, were first conducted under different normal stresses and moisture contents. Four various types of shear-tensile failure modes, i.e., climbing failure, climbing-gnawing failure, gnawing failure and sliding failure, were observed for the combination of hard layers; while three diverse types of shear-tensile failure modes, i.e., disengaging failure, dislocating failure and gnawing failure, were observed for the combination of soft–hard layers. Subsequently, the Two Dimensional Particle Flow Code discrete element method (PFC 2D DEM) was used for the numerical simulations, in which the meso-damage evolution process of the rock discontinuities was simulated, and the variation laws of the meso-damage crack number and energy were obtained. Based on the good agreement between the experimental observations and numerical results, a shear strength equation for the rock discontinuities was proposed, and its rationality was validated by comparing the factor of safety (FOS) of a slope calculated by the limit equilibrium method (LEM) and the strength reduction method (SRM).

自2003年蓄水以来，三峡库区（TGRA）经常在具有典型锯齿状岩石间断的分层岩石斜坡上发生大量的滑坡，其中锯齿状岩石间断的剪切力学行为一直存在。很少有学者探讨过。在这项研究中，采用实验和数值方法研究了两种不同岩性组合类型下多尺度三角形凹凸不平岩石间断的宏观介观剪切力学行为。硬层和软层分别是取自TGRA的石灰岩和黏土，硬层组合和软硬层组合的正常加载速率分别为0.5 kN / min和0.05 kN / min。 ，两种不同岩性组合类型的剪切加载速率为0.5 kN / min。首先在不同的法向应力和含水量下对具有不同的一阶凹凸角（即30°，45°和60°，以及相同的二阶凹凸角）的岩石间断进行了实验室直接剪切试验。 。对于硬质层的组合，观察到四种不同类型的剪切拉伸破坏模式，即爬升破坏，爬升咬合破坏，咬合破坏和滑动破坏。对于软硬结合层，观察到三种不同类型的剪切拉伸破坏模式，即脱开破坏，错位破坏和咬合破坏。随后，使用二维粒子流代码离散元方法（PFC 2D DEM）进行了数值模拟，模拟了岩石间断面的细观破坏演化过程，得到了细观破坏裂纹数和能量的变化规律。基于实验观察结果与数值结果之间的良好一致性，提出了岩石不连续面的抗剪强度方程，并通过比较极限平衡法（LEM）计算的边坡安全系数（FOS）验证了其合理性。以及强度折减法（SRM）。