含弱层边坡分区滑动破坏模式及演化规律研究

Study on regional sliding failure modes and evolution regularity of slopes with weak layers

含弱层岩石边坡的破坏模式及滑坡机制对露天矿边坡稳定性研究具有重要意义。基于极限平衡理论建立含弱层岩石边坡分区滑动力学模型,将弱层上部坡体分为稳定区-欠稳区-失稳区,推导三区力学平衡方程与坡体稳定差函数,研究含弱层边坡分区稳定性的影响因素,揭示欠稳区是形成大型滑坡的关键区域。并进行边坡分区滑动破坏过程的底摩擦模型试验,验证了理论结果。研究表明:分区滑动破坏是含弱层岩石边坡的典型破坏模式,弱层倾角是影响稳定区-欠稳区-失稳区三区分布的决定性因素,坡体欠稳区后端对倾角的敏感性较高。倾角较小的坡体三区分布较为均匀,倾角较大的坡体,角部稳定性越低。最后,以弓长岭露天铁矿何家采区北帮滑坡为背景,验证了分区滑动破坏模式的准确性,研究成果可为类似含弱层岩石边坡稳定性的研究和治理提供借鉴。

Failure modes and landslide mechanisms of rock slopes with weak layers are of great significance to the study of the stability of open-pit mine slopes. Based on limit equilibrium theory,a regional sliding mechanical model of rock slopes with weak layers is established. The slope above the weak layer is divided into stable region,understable region and unstable region. Mechanical equilibrium equations of the three regions and the stability difference function of the slope are derived. Influence factors of the slope regional stability with a weak layer are studied,and it is revealed that the understable region is the key area of large landslides. The base friction model test of sliding failure process is carried out,and theoretical results are verified. The study shows that regional sliding failure is a typical failure mode of rock slopes with a weak layer,and that the dip angle of the weak layer is the decisive factor affecting the distribution of the stable,understable and unstable regions and that the back end of the understable region of the slope is more sensitive to the dip angle. The slope with a smaller dip angle is more evenly distributed in the three regions,and the slope with a larger dip angle is less stable at the corner. Finally,taking the north landslide in Hejia mining area of Gongchangling open-pit iron mine as the background,the accuracy of the regional sliding failure mode is verified. The research results can provide reference for the research and treatment of similar rock slopes with weak layers.