Soft Rock Cutting Mechanics Model of TBM Cutter and Experimental Research

On the basis of brittle tensile fracture theory, assuming the destruction of rock was due to tensile failure, a cutting-tool loading calculation model was established, considering the compact core impact in front of cutting-tool, then the mechanism of cutter-rock, as well as the process of brittle fracture of rock were analyzed and the expressions of horizontal cutting force and vertical propulsive force for the shield cutter were obtained. At the same time, three kinds of cutters with different rake angle were designed, and the cutting experiments on a linear cutting performance testing station were carried out. By comparing, the results of experiments were basically in accordance with those of mechanical model, error rate of horizontal cutting force was below 7% and that of vertical propulsive force was in the scope 9%. At last, the experiments proved that the force of cutter would increase along with the increasing depth, or decreasing rake angle.