Study on the Influence of Different Control Modes on TBM Disc Cutter Performance by Rotary Cutting Tests

A full-scale rotary cutting tests using the fixed penetration and the fixed normal force modes were conducted to investigate the rock cutting behaviours and mechanisms under the TBM disc cutter. In both control modes cutting the grout specimen, the normal forces were found to increase with cutter penetration,the rolling forces were found to increase with the penetration in linear function relations,the cutting coefficients were found to increase with the penetration in linear function relations,the specific energies were found to change with the penetration following quadratic function relations, and the rock boreability indices were found to decrease with the penetration in power function relations. At the same penetration, the normal force, rolling force, cutting coefficient, specific energy and rock boreability index in the fixed normal force mode were all found to be lower than the corresponding values in the fixed penetration mode. Thus, it can be concluded that the rock cutting efficiency in the fixed normal force mode is higher than that in the fixed penetration mode when cutting the grout specimen.