Energy-Based Volumetric Rock Destruction Criterion in the Rotary–Percussion Drilling Technology Improvement

Abstract

Efficiency of energy-based criterion of volumetric rock destruction in estimation of drilling technology is theoretically validated and experimentally proved in in-situ rotary–percussion drilling in mines in Russia. The criterion is adapted to the performance of various drilling units by means of introduction of empirical coefficients for transformation of drilling energy intake to the relevant energy characteristics of stress rock fracture in face zone. The mathematical description of the criterion of minimum energy intake of rotary–percussion drilling depending on stress state and physical properties of rocks, and on force of rotary–feed mechanism is presented. The authors introduce a new geomechanical notion—factor of topological connection of rocks and give its analytical expression using experimental uniaxial compression and uniaxial tension strength of rocks, required in the design and improvement of rotary–percussion drilling in different geological and geotechnical conditions of mining.