Mechanical mining and excavation in deep metal mines can be regarded as the process of crushing hard rock by conical pick indentation. In this study, a confining pressure loading device was designed and used to carry out dynamic conical pick indentation crushing tests under confining pressure conditions on three types of granite with varying strengths, using the Split Hopkinson Pressure Bar (SHPB). The objective was to quantitatively investigate the effect of confining pressure and rock strength on the indentation crushing characteristics of deep hard rocks. The results indicate that as the confining pressure increases from 5 MPa to 20 MPa, the dimensional parameters such as volume, diameter and depth of the impact groove decrease linearly, while parameters such as the specific energy, indentation force, indentation index and energy utilization rate progressively increase. The increase in the confining pressure inhibits the formation of internal cracks in the rock, enhancing its resistance to pick indentation, which in turn makes rock fragmentation more difficult. This creates unfavorable conditions for efficient rock breaking. Furthermore, rock strength plays a crucial role in the pick indentation process. The higher the rock strength, the greater its resistance to pick indentation, leading to increased energy consumption, accelerated wear of the conical picks, and reduced efficiency in rock breaking.

中文翻译：

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围压下动态锥形镐压痕使硬岩碎裂


深部金属矿中的机械采矿和开挖可以看作是通过锥形镐压痕破碎硬岩的过程。本研究设计了一种围压加载装置，并使用分体式霍普金森压力杆 （SHPB） 对三种不同强度的花岗岩进行围压条件下的动态锥形截齿压痕破碎试验。定量研究围压和岩石强度对深部硬岩压痕破碎特性的影响。结果表明：随着围压从5 MPa增加到20 MPa，冲击槽体积、直径、深度等尺寸参数呈线性减小，比能量、压痕力、压痕指数和能量利用率等参数逐渐增加。围压的增加抑制了岩石内部裂纹的形成，增强了其对镐压痕的抵抗力，进而使岩石破碎更加困难。这为高效破石创造了不利条件。此外，岩石强度在截齿压痕过程中起着至关重要的作用。岩石强度越高，其对镐形压痕的抵抗力就越强，从而导致能耗增加，锥形镐的磨损加速，岩石破碎效率降低。