Study on rock fracture mechanism based on the combustion and explosion characteristics of high-energy expansive agent

Abstract

In this paper, a new rock breaking technology based on high energy expansive agent (HEEA) is proposed. The components producing gas and work capacity of HEEA were studied by means of closed explosion system, specific volume test system and oxygen bomb calorimeter system. The results show that the gas produced by the agent consists of harmless water vapor, nitrogen, carbon dioxide and so on. The pressure inflection point of the agent is 5 MPa, the peak pressure is 70 MPa, and the specific volume is 702.4 L/kg. The calculation shows that it has enough rock breaking ability. According to the properties of HEEA, the unit agent consumption experiment of rock breaking were designed, and rock breaking laws of agents were studied by combining computed tomography and 3D reconstruction technology. When the single agent consumption is 0.2, the fracture volume and area are 25.6 cm3 and 650 cm2, fracture density and fractal dimension are 0.65 m−1 and 2.404, respectively, the rock breaking effect is the best. Based on HEEA properties and rock breaking law, the mechanism of rock breaking by combustion-detonation is proposed, provided guiding suggestions for engineering applications.