Layered rock slopes naturally formed or excavated are prone to buckling failure. Current assessment methods predominantly rely on flexural buckling theory (i.e., elastic instability), but in fact this type of destabilization rarely occurs. Thus, an applicable stability evaluation method is urgently needed. Based on the upper bound theorem, this study develops a three-hinge buckling (THB) kinematic mechanism for layered rock slopes, incorporating translational/rotational rigid blocks and triangular plastic hinges. An efficient solution scheme combining a two-step searching genetic algorithm and the strength reduction method is proposed to determine both the minimum factor of safety (FoS) and critical failure mechanism. The validity of the upper bound solutions is verified through discrete element method (DEM) simulations of THB experiments. Furthermore, two buckling events on the Lavini di Marco slope are analyzed using the presented method and the effects of pore water pressure, thickness of the sliding mass and spacing of bedding joints on stability are systematically investigated. The derived critical failure mechanisms align closely with field-observed buckling phenomena, reinforcing the method's reliability. This study advances the understanding of THB failure while providing engineers with a practical tool for assessing buckling stability in stratified rock slopes.

中文翻译：

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层状岩质边坡三铰链屈曲破坏的上限法

自然形成或开挖的层状岩石边坡容易发生屈曲破坏。目前的评估方法主要依赖于弯曲屈曲理论（即弹性不稳定），但实际上这种类型的不稳定很少发生。因此，迫切需要一种适用的稳定性评价方法。基于上界定理，本研究开发了一种用于层状岩石边坡的三铰链屈曲 （THB） 运动机构，包括平移/旋转刚性块和三角形塑性铰链。该文提出一种结合两步搜索遗传算法和强度折减法的高效求解方案，用于确定最小安全系数（FoS）和临界失效机制。通过 THB 实验的离散元法 （DEM） 仿真验证了上限解的有效性。此外，使用该方法分析了 Lavini di Marco 斜坡上的两个屈曲事件，并系统研究了孔隙水压力、滑动质量厚度和层理节理间距对稳定性的影响。推导的关键失效机制与现场观察到的屈曲现象密切相关，增强了该方法的可靠性。这项研究促进了对 THB 破坏的理解，同时为工程师提供了评估分层岩石边坡屈曲稳定性的实用工具。