水射流构造自由面下滚刀线性切割破岩特性研究

Study on the rock-breaking characteristics of linear cutting by a hob under a free-face generated by a water jet

为了分析水射流构造自由面情况下的滚刀切割破岩特性,本文采用有限元模拟分析方法,建立自由面工况下滚刀破岩模型,模拟不同切宽下滚刀切割岩石动态过程,得到水射流构造自由面工况下滚刀破岩载荷、破岩状态等变化规律,并利用线性切割实验进行验证。研究结果表明:水射流构造自由面后滚刀切割过程中,岩石会产生表面和内部拉伸裂纹,且当切宽小于临界值50 mm时,滚刀临近自由面侧的拉伸裂纹可以延伸到自由面,促进岩石破碎;水射流构造自由面情况下的滚刀破岩垂直载荷最大,侧向载荷最小,且合适的切宽可以显著改善滚刀受载;当滚刀能有效利用水射流构造的自由面破岩时,其破岩比能耗远低于无自由面效应下的滚刀破岩比能耗,前者仅约为后者的30%,破岩效率得到显著提高。研究结果可为水射流辅助滚刀破岩参数设计提供依据。

To examine the rock-breaking characteristics induced by the hob under a free-face condition caused by a water jet,a rock-breaking model of the hob under a free-face condition was developed based on the finite element simulation method,and the rock-cutting process of the hob under different-cutting widths was simulated,achieving the variation laws of rock-breaking force and rock-breaking state under the free-face condition caused by the water jet.The simulation was confirmed by the linear-cutting experiment.The findings revealed that the cutting process of the hob may produce tensile cracks on the surface and inside the rock sample under the free-face condition genera-ted by the water jet.When the cutting width is less than the critical value of 50 mm,the tensile cracks near the free face can extend to the free face and advance rock fragmentation.For cutting rock under the free-face condition produced by the water jet,the vertical force of the hob is the largest and the lateral force is the smallest,and the suitable cutting width can remarkably enhance the cutting force of the hob.When the hob can effectively utilize the free face to break the rock,the specific energy consumption is much lower than that without the free surface effect.The former is only about 30%of the latter,and the rock-breaking efficiency is significantly enhanced.This work offers guidance for designing rock-breaking parameters in the rock-breaking process assisted by water jets.