In this study, several wall deterioration mechanisms are identified for a 3 m diameter bored raise at a hard rock mine in Sudbury, Ontario, Canada, through taking high precision LiDAR scans, recording seismicity, and direct field observations in the raise. It is found that four factors influence the deterioration of the raise, which are stress change as the excavation is made, local geological structure, slashing-induced stress changes, and scouring of the raise as it was cut and as broken rock was dumped down the raise. It is also found that these multiple factors are often working simultaneously, leading to overbreak beyond the original bored dimension. The findings are useful for improving understanding of brittle rock failure, achieving a better understanding of the deterioration mechanisms for mechanical cut raises in hard rock, calibrating numerical models, and making better engineering decisions for ground support and precondition blasting to improve the health and safety for workers.

在这项研究中，通过进行高精度LiDAR扫描，记录地震活动和在凸起处进行直接野外观测，确定了加拿大安大略省萨德伯里一个硬岩矿中3 m直径钻孔凸起的几种壁面破坏机理。发现有四个因素会影响凸起的恶化，即开挖过程中的应力变化，局部地质结构，切割引起的应力变化以及凸起被切割和碎石倾倒时的冲刷。提高。还发现这些多个因素通常同时起作用，导致超出原始钻孔尺寸的破坏。这些发现有助于增进对脆性岩石破坏的理解，更好地了解硬岩中机械切屑的恶化机理，