Abrasive Wear Process of TBM Disc Cutter and Its Effects on Cutting Performance

Therefore, it is of great significance to carry out research on the influence of cutter blade shape and wear on rock breaking performance to guide the selection of cutters in engineering practice and the design of new cutters with high efficiency and low wear. This paper establishes a three-dimensional discrete element finite difference coupling model of rock breaking of cutters for commonly used flat cutters and circular cutters, and conducts the cutter penetration test by designing the relevant examples, which compares and illustrates the superiority and applicability of the coupling model in calculation.

Based on the numerical simulation method and abrasive wear removal mechanism, the wear depth of the cutter is solved by segmented superposition calculation, and the wear history of the flat and circular cutter with two types of blade shapes is realized; at the same time, the evolution law of the cutter's rock breaking performance is studied based on the trend of the cutter's rock breaking volume, load, number of cracks, and other simulation results during the wear process.

The results showed that the cross-section profile of the cutters has a significant effect on its rock breaking performance, and the specific energy of the circular cutter is lower than that of the flat cutter; the reason for this is that the load difference between different blade shapes of the cutter dominates the effect of specific energy in rock breaking, and the circular cutter requires less breaking force and less work, so the specific energy is lower than that of the flat cutter.

When the flat cutter acts with the rock, the contact stress distribution of the cutter-rock contact stress is more uniform in the direction of the blade width, while the contact stress at the top of the blade of the circular cutter is the largest, and the two sides are low, which leads to the basic unchanged blade shape of the flat cutter after abrasion, and the blade shape of the circular cutter is in gradual transition from curved blade to flat blade; in addition, compared to flat cutter, circular cutters are less stable in terms of rock-breaking performance during the wear process, and the rock breaking performance gradually evolves to the flat cutter, which can only show its low energy consumption rock breaking advantage in the early stage of rock-breaking; on the contrary, the flat cutter, as a constant cross-section cutter, has better stability of its rock-breaking performance in the wear process.