Theoretical Study on Flat Tooth Cone Fracture Type Rock Breaking based on Plane Indentation

During rock breaking by drill, cone rolls on the rock surface, and contact between gear teeth and the surface is positive Mode-I plane indentation and bias Mode-I plane indentation. During bias action, there will be an asymmetrical Mode-I singular stress field at both ends of the indenter. The stress field singularity is of the same order as the Mode-I crack tip and with the same function distribution. In this paper, based on J 2 integral conservation law, a new method is established for solving the stress intensity factor of bias Mode-I plane indentation, which not only provides respective stress intensity factor of both ends of indenter but also compares relations between eccentricity, partial load and stress intensity factor. The study not only provides a method for the establishment of a new cone drill engineering design but also improves rock layer boring efficiency.