Three-Dimensional Numerical Simulation of Rock Breaking by the Tipped Hob Cutter Based on Explicit Finite Element

As an important equipment for wellbore construction, the raise boring machine (RBM) has been widely used in subway tunnels and mine construction projects. Its tipped hob cutter for rock breaking is directly related to the cost, safety, and overall performance of the project. However, few open studies research on the rock-breaking by the tipped hob cutter, and there is still a lack of enough understanding of how the cutter breaks rock and the form of the rock breaking. In this paper, we study how the tipped hob cutter breaks the rock, and how to establish the finite-element model of the rock breaking by the cutter, with using the numerical simulation software LS-DYNA to analyze the rolling process and rock fracture form of the cutter. By studying the fracture morphology of rocks, it is proposed that there are three fracture modes of rock breaking: forward slip, no slip, and backward slip, using the experimental verification. On this basis, study the variation laws and correlations of feed force, lateral force, and positive force under different moving speeds and penetration depths. The results in this paper can provide a theoretical basis for improving the tool design of the tipped hob cutter on the RBM against the efficiency of rock-breaking.