Study on the rock-breaking characteristics of linear cutting by a hob under a free-face generated by a water jet
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.
water jetfree facefinite element simulationhobrock cuttingcutting widthrock-breaking forcerock-breaking efficiency
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维普
