From lab forces to field lifespans: How rock and operating parameters govern TBM disc cutter wear

Tunnel boring machines (TBMs) are considered a reliable and fast method for boring long tunnels. However, the wear and failure of disc cutters in hard rock influences the efficiency of equipment, ultimate timeline, and project cost. Therefore, estimating the cutter life under different geomechanical conditions is crucial for TBM manufacturers and tunnel engineers. This study investigates the influence of geomechanical factors, including elastic modulus ( E ), uniaxial compressive strength ( σ c ), confining stresses, and TBM operational parameters such as penetration rate ( P ) and disc cutter inclination angle ( ϕ ), on disc cutter wear using the explicit finite element method. The results revealed that the uniaxial compressive strength, disc cutter inclination angle, rock elastic modulus, and confining stresses, in that order, had the greatest impact on the cutter wear rate. Such that an increase in compressive strength from 31 MPa to 137.9 MPa caused a 2.4-fold reduction in cutter life. Meanwhile, the cutter life in the rock without confining stress was only 15% greater than in the sample under 15 MPa of confining stress. Additionally, to achieve the most optimal and economical drilling conditions, the penetration depth of the disc cutters should be optimized based on the existing conditions. Since the installation location of the disc cutters, their spacing and rotational trajectory significantly influence wear levels, a full-scale simulation of a TBM is conducted according to a real case study. The comparison of results indicated that the proposed method has high capability in estimating the cutter life under various geomechanical conditions. • Rock-cutter interaction is simulated by an explicit FEM to estimate wear of disc cutter. • Inclined cutters face higher wear than vertical ones due to increased lateral forces. • Perpendicular stresses playing a more critical role on wear than those aligned with cutting. • Elastic modulus increases raise wear rates, though its influence tapers at higher values.