Rock excavation by disc cutter

Partial factorial experiments have been undertaken to study the effect of changing the principal geometrical variables on the performance of disc cutters operating in both the unrelieved and relieved cutting modes. A simple mathematical model is proposed which, on the evidence of the experimental data, is found to provide a good description of the magnitude and variation of thrust and rolling forces with disc diameter, edge angle and penetration. Further analysis shows the maximum separation between adjacent discs operating in array to be governed by the compressive to shear strength ratio for the rock. An examination of the published results of others in this field supports the belief that the disc model is valid.