厚层硬岩采动斜坡溃屈破坏规律研究

STUDY ON BUCKLING FAILURE LAW OF THICK HARD ROCK MINING SLOPE

厚层硬岩采动斜坡受结构面切割形成的块体高径比控制,可能发生整体倾倒、剪切滑移或底部溃屈进而产生大规模崩塌。但块体高径比对厚层硬岩采动斜坡破坏规律的影响仍不清楚。本文以贵州省纳雍县张家湾镇普洒村崩塌为原型,采用离散元方法研究了块体高径比对厚层硬岩采动斜坡变形破坏规律的影响,结果表明:岩体高径比为2∶1时,厚层硬岩采动斜坡宏观变形现象以裂缝发育为主;岩体高径比大于3∶1时,斜坡以坡脚溃屈-坡顶崩塌的模式发生破坏,高径比大于4∶1时崩塌规模明显增大。最后提出了破坏面水平深度与岩体高径比的关系式用于预测破坏面位置。所得结果为柱状岩体发育的厚层硬岩采动斜坡破坏模式分析提供依据,也可用于该类采动斜坡最大崩塌规模的预测。

When cutting through structural surfaces during thick hard rock mining,the height-to-diameter ratio of the blocks formed can greatly impact the stability of the slopes.This can result in various types of mass failures such as overturning,shear slip,or bottom failure.However,the effect of block height-to-diameter ratio on the damage pattern of mining slopes in thick hard rock is still unclear.This paper takes the collapse of Pushan Village,Zhangjiawan Town,Nayong County,Guizhou Province as a representative case.The discrete element method has been employed.The investigation focuses on the impact of block height-to-diameter ratio on the deformation and damage law of thick hard rock mining slopes.The results show that the macro deformation phenomenon of thick hard rock mining slopes is influenced by the development of cracks,particularly when the height-to-diameter ratio of the rock body is 2∶1.When the height-diameter ratio of rock mass exceeds 3∶1,the slope undergoes destruction through the mechanism of slope toe buckling and slope top collapse.When the height-to-diameter ratio exceeds 4∶1,there is a noticeable increase in the collapse scale.Lastly,a relationship equation is proposed to predict the location of the damaged surface by taking into account the damaged surface's horizontal depth and the rock mass's height-to-diameter ratio.The findings derived from this study provide a fundamental foundation for the analysis of damage characteristics in thick-layered hard-rock mining slopes that encompass columnar rock formations.Additionally,the results can be utilized in predicting the maximum collapse size for this type of mining slope.