软硬互层顺层岩质边坡破坏试验

软硬互层结构的顺层岩质边坡破坏类型复杂、难于防治, 针对此类边坡地质灾害易发、多发的问题, 从坡面角度、岩层倾向及组合形式、节理分布等方面进行了研究。边坡物理模型试验是揭示边坡变形破坏机理的重要手段, 基于相似理论, 以重庆市万州区孙家滑坡为工程依托, 根据滑坡区地质勘探报告设计了室内边坡物理模型试验; 试验通过顶升模型箱模拟重力加载来探究顺层岩质边坡发生破坏时, 前缘坡角和软弱夹层倾角之间的关系; 结合有限元分析软件Plaxis 2D对物理模型进行了多组数值模拟试验, 以验证软硬互层顺层岩质边坡破坏机制。试验结果表明: 对于顺层岩质边坡, 当软弱夹层的倾角在22°左右, 前缘开挖坡角58°左右时, 顺层岩质边坡容易发生滑动, 滑动面为后缘节理面和软弱夹层的贯通面。因此, 顺层岩质边坡稳定性受层面和节理面密度的控制, 当边坡含多层软弱层面时, 易沿层面和后缘节理贯通面发生破坏, 随着软弱面层数增加, 边坡稳定系数逐渐降低。研究成果可以为公路开挖切坡导致的顺层岩质边坡失稳机理研究及其稳定性评价提供理论依据, 为顺层岩质边坡失稳的预测预报提供支撑。 

Failure experiment of soft-hard interlayer bedding rock slope

Bedding rock slopes with soft-hard interlayers have complicated failure types and are difficult to prevent. In view of the prone and frequent occurrence of such slope geological disasters, research is carried out from the aspects of slope angle, rock formation tendency and combination form, and joint distribution.Slope physical model testing is an important means to reveal the mechanism of slope deformation and failure.Based on similarity theory, this paper takes the Sunjia landslide in Wanzhou District, Chongqing City, as the engineering support and designs the indoor slope physical model test according to the geological exploration report of the landslide area.The test simulates gravity loading through a jack-up model box and explores the relationship between the front slope angle and the weak interlayer inclination when the bedding rock slope slope is damaged.Combined with the finite element analysis software Plaxis 2D, multiple sets of numerical simulation tests were performed on the physical model to verify the failure mechanism of bedding rock slopes with soft-hard interlayers. The results show that for a bedding rock slope, when the inclination angle of the weak interlayer is approximately 22°, the leading edge excavation slope angle is about 58°, the bedding rock slope is prone to sliding, and the sliding surface is the joint surface of the trailing edge and the weak interlayer. Through the surface.Therefore, the stability of a bedding rock slope is controlled by the density of the layer and the joint surface. When the slope contains multiple weak layers, it is easy to break along the layer and the back edge of the joint. As the number of weak surfaces increases, the slope stability coefficient gradually decreases.The research results can provide a theoretical basis for the instability mechanism and stability evaluation of bedding rock slopes caused by road excavation and slope cutting, and provide support for the prediction of the bedding rock slope instability.