Pre-slotting rock is an effective method for improving the rock cutting performance of mechanical cutting tools. A method of rock cutting using a disc tool assisted by vertical pre-slotting on free-face has been proposed, and in this paper, the effect of the number and configuration of pre-slots on the improvement of rock cutting performance is evaluated. The progress of crack propagation is analyzed, and the underlying mechanism is revealed under different pre-slots conditions with the help of DEM. Considering the effect of confining stress under actual conditions, the rock cutting performance using a disc tool and the enhancing effect of pre-slots are investigated. The results show that the mean cutting force decreases with increasing pre-slots spacing when the pre-slots spacing is less than the diameter of the disc tool, and the reducing ratio of the cutting force is more than 40 % with 80 mm spacing under the two pre-slot conditions. A large number of pre-slots destroy the integrity of the rock, and the cutting force under the condition of four or five pre-slots decreases by more than 50 %. The confining pressure suppresses the propagation of tensile cracks, the cutting force increases linearly, and the ratio of tensile to shear cracks decreases with increasing confining pressure. The confining pressure weakens the improvement effect of pre-slots assisting rock cutting using a disc tool to a certain extent, while under the condition of five pre-slots, the improvement is further developed, in which the cutting force decreases by 60 % at a 20 MPa confining pressure.

中文翻译：

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使用盘式刀具辅助自由面垂直预开槽进行岩石切割


岩石预开槽是提高机械切削刀具切削岩石性能的有效方法。提出了一种利用圆盘刀具辅助自由面垂直预开槽切削岩石的方法，并评估了预开槽的数量和配置对提高岩石切削性能的影响。分析了裂纹扩展的过程，并借助 DEM 揭示了不同预开槽条件下裂纹扩展的潜在机制。考虑实际条件下围压的影响，研究了圆盘刀具的岩石切削性能和预制槽的增强效果。结果表明，当预槽间距小于圆盘刀具直径时，平均切削力随着预槽间距的增大而减小，且在80 mm间距下，切削力降低率超过40%。两个预时隙条件。大量预槽破坏了岩石的完整性，四、五个预槽条件下切削力下降50%以上。围压抑制拉裂纹扩展，切削力线性增加，拉剪裂纹比随围压增加而减小。围压在一定程度上削弱了预槽辅助圆盘刀具切削岩石的改善效果，而在5个预槽条件下，改善效果进一步发展，切削力在一定条件下下降了60%。 20 MPa 围压。