A brief review of Soviet theoretical approaches to dynamic rock failure

Abstract

To develop a CAD/CAM model of a machine excavation, mathematical models for the rock destruction process are needed. It is known that rock destruction under indentation includes such stages as: rock deformation, surface crushing, formation of destruction nucleus, formation of Hertzian cone crack, squashing of cone (the rock bounded by a Hertzian cone crack), spalling of rock between the Hertzian crack and the free surface. The term destruction nucleus or destruction kernel means the zone of confining pressure under the indentor-rock contact surface in which the rock is crushed. Rock destruction in cutting occurs in a similar manner Rock destruction is a complex process which includes cracking, elastic and plastic deformation, wave propagation and cannot be described by simple methods. The review here provides a description of investigations in mathematical modelling of rock destruction for drilling (which were carried out mostly by Soviet investigators) and the applicability of different methods for the solution of applied problems. The principal ideas and the results of a number of investigations based on the methods of elasticity, plasticity, fracture and wave theories are given in Tables 1-4.