黄达, 马昊, 孟秋杰, 等. 2021. 反倾软硬互层岩质边坡倾倒变形破坏机理与影响因素研究[J]. 工程地质学报, 29(3) : 602-616. doi: 10.13544/j.cnki.jeg.2020-417.
    引用本文: 黄达, 马昊, 孟秋杰, 等. 2021. 反倾软硬互层岩质边坡倾倒变形破坏机理与影响因素研究[J]. 工程地质学报, 29(3) : 602-616. doi: 10.13544/j.cnki.jeg.2020-417.
    Huang Da, Ma Hao, Meng Qiujie, et al. 2021. Study on toppling mechanism and affecting factors of anti-dip rock slopes with soft-hard interbedded structure[J]. Journal of Engineering Geology, 29(3): 602-616. doi: 10.13544/j.cnki.jeg.2020-417.
    Citation: Huang Da, Ma Hao, Meng Qiujie, et al. 2021. Study on toppling mechanism and affecting factors of anti-dip rock slopes with soft-hard interbedded structure[J]. Journal of Engineering Geology, 29(3): 602-616. doi: 10.13544/j.cnki.jeg.2020-417.

    反倾软硬互层岩质边坡倾倒变形破坏机理与影响因素研究

    STUDY ON TOPPLING MECHANISM AND AFFECTING FACTORS OF ANTI-DIP ROCK SLOPES WITH SOFT-HARD INTERBEDDED STRUCTURE

    • 摘要: 倾倒变形常见于反倾结构边坡,特别在具有软硬互层结构边坡中,甚至可发育为深度上百米的大型滑坡。为进一步探明此类反倾边坡倾倒变形的破坏机制,以及边坡形态结构及岩体力学参数等因素的影响规律,以离心模型试验为原型,结合离散元数值模拟,分析了倾倒变形的形成过程以及在外界扰动下的破坏机制。并通过单因素分析法、正交设计法等,研究了多种因素对反倾边坡倾例变形的影响,通过极差分析获得了各因素的敏感性。通过在岩层内预置大量多边形随机裂隙,数值模拟较好地实现了对破裂面起裂及延展规律的模拟。结果表明:离心模型试验可较好地还原倾倒变形过程,而离散元数值模拟则可对实验结果进行有效的重现与扩展,两者吻合度良好;岩体变形过程存在3个阶段,即起始变形、稳态变形和失稳破坏等阶段;破裂面呈弧形,在变形积累到一定程度后快速形成;边坡可自下而上形成多级破裂面,并伴随岩层的强烈弯曲变形,在外界扰动下,倾倒变形体将由外到内沿不同破裂面形成渐进后退式破坏;多种影响因素中,边坡形态结构影响最大,层面参数次之,软硬岩岩石力学参数的差异影响较小;具体而言,边坡形态与坡体结构对倾倒变形的影响性大小表现为坡角>倾角>坡高>坡形>层厚比>层厚,坡角、倾角、坡高越大,坡形越外凸,软硬岩层厚差越小,倾倒变形越容易发生;边坡变形规模主要受形态结构因素控制,倾角和坡角影响最显著。

       

      Abstract: In the Three Gorges Reservoir area, there are many anti-dip slopes with soft-hard interbedded structures in the Gongjiafang-Dulong section of Yangtze river, and the phenomena of flexural toppling are developed. This paper explores the mechanism of flexural toppling, as well as the effect of slope morphology, structure, and mechanical parameters of rock mass on the toppling. Based on the centrifugal model test and discrete element numerical simulation, this paper analyzes the toppling process of soft-hard interbedded toppling slopes and the failure mechanism under external disturbance. The single factor analysis method and orthogonal design method are combined to study the influence factors of toppling. And the sensitivity of each factor is obtained by range analysis. The random fractures are preset in the rock strata to get the initiation and extension laws of the fracture surfaces. The results show that the centrifugal model test and the discrete element simulation can well reproduce the toppling process, and the coincidence between them is good. The toppling process can be divided into three stages: initial deformation, steady deformation, and unstable failure. After the rock bending accumulates to a certain extent, the arc fracture surfaces form rapidly. The slope can form a multi-level fracture from bottom to top. Under the external disturbance, the toppling part can gradually form progressive backward collapse along different fracture surfaces from the outside to the inside. The stability of the anti-dip slope is mainly affected by the slope shape and structure. The sensitivity of influence factors is as follows: slope angle>dip angle>slope height>slope shape>layer thickness ratio>layer thickness. The larger the slope angle, dip angle and slope height are, the more convex the slope shape is, the smaller the thickness difference between soft and hard strata is, and the easier the slope is to be damaged. The slope damage scale is mainly controlled by the dip and slope angle. The research results have guiding significance for the reinforcement and treatment of such slopes.

       

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