Numerical and Experimental Studies on the Effects of the TBM Cutter Profile on Rock Cutting

This paper explores the effect of the profile of tunnel boring machine (TBM) cutters on the rock cutting performance via the use of a particle flow discrete element model. Two of the most commonly used cutters, namely a flat-tip cutter and a circular-tip cutter, are considered in the study. Reduced-scale rotary rock cutting experiments are performed to verify the key conclusions obtained by the numerical analysis. The results from both the simulations and experiments indicate that, at the same penetration depth, the volumes of rock chips produced by the two cutters are similar, but the normal force of the circular-tip cutter is much smaller than that of the flat-tip cutter, leading to a lower specific energy. Contact analysis implemented by a finite element model further reveals that the stress field caused by the circular-tip cutter has a higher magnitude and is concentrated in a smaller area, indicating that the circular-tip cutter could penetrate the rock with lower normal force and produce less rock powder, which could avoid excessive rock broken.