Formation of an incipient crack in the impact fracture of a brittle body by a wedge

A study is made of the problem of the penetration of a wedge-shaped tool in rock. It follows from the solution of the problem in the elastoplastic formulation that the continuation of the axis of the wedge in the elastic region includes a zone in which the rock is subjected to tension perpendicular to the axis. In accordance with the kinetic thermofluctuation theory of strength, this determines the formation and propagation of microcracks oriented along the wedge axis. A computer model is proposed to describe the process of random accumulation of microdefects in a loaded solid body. The model is used to create an algorithm to calculate the formation and development of an incipient crack before the vertex of the wedge. The length of the crack is determined by the properties of the medium and the parameters of the penetrated tool.