Full-scale linear cutting tests to check and modify a widely used semi-theoretical model for disc cutter cutting force prediction

This study is to investigate the change in resultant force, cutting coefficient and normalized resultant force of the TBM (tunnel boring machine) disc cutter when using different cutting conditions and different linear cutting machines. Full-scale linear cutting tests on three rocks of different compressive strengths were conducted. The experimental results, combined with other previously published data, were compared to the prediction results of the semi-theoretical CSM (Colorado School of Mines) prediction model. The influences of rock compressive strength, disc cutter diameter and machine frame stiffness on the comparison results were analysed. From the general view, experimental resultant forces tend to be underestimated while experimental cutting coefficients and normalized resultant forces both tend to be overestimated when using the semi-theoretical CSM prediction model, and the underestimation or overestimation degrees are different when the above three influencing factors are different. The reason responsible for these phenomena can be mainly attributed to the lower actual cutter penetration depth compared to the pre-set one during the rock–machine interaction process. The results of this study can offer more accurate understanding of the full-scale linear cutting tests using different cutting conditions and different linear cutting machines, and thus it can contribute to the more reliable and accurate prediction on disc cutter cutting forces.