MECHANICAL TUNNEL BORING PREDICTION AND MACHINE DESIGN

A comprehensive theoretical analysis of the interaction of a disc roller cutter with hard, brittle rocks was undertaken. Predictor equations were modified to consider the effect of cutter wear. Testing was undertaken both with sharp and artificially dulled disc cutters. Results indicated that penetration, spacing, and edge angle are highly significant variables affecting cutter performance. To simulate, the multiple cutter patterns found in the field were undertaken to experimentally study the effects of different modes of cutting. Theoretical force values calculated by using the developed predictor equations were found to agree with laboratory observations. The scaling of the small and large-scale cutting results appeared to be possible. The field boring data from an experimental tunnel boring site was used to check the validity of the predictor equations for field boreability predictions. A computer program designed to predict field boring performance was written.