The electrical discharge characteristics and ignition mechanism of coal mine roof fracture under stress

Abstract

Underground goaf is a high-risk area of thermodynamic disaster accidents in coal mines, and the thermodynamic disaster accidents occurring in goaf may be inextricably linked with the activities of the roof. This paper conducts in-depth research on the instantaneous electrical discharge characteristics and ignition mechanism induced in the process of rock damage by building a force-electric ignition experimental system. The results showed that the electric discharge generated by rocks during the fracture process could penetrate air and produce the photoelectric effect. The instantaneous electric discharge capacity and luminous intensity generated during rock fracturing were mainly affected by the quartz content and compressive strength of the rock, and the experiment confirmed that the electrical discharge of rocks during the fracture process can ignite methane-air. The piezoelectric effect during the loading process of rocks can significantly enhance their electric discharge capacity. In this paper, the viewpoint that the electric discharge of coal seam roof in the process of fracturing ignites the methane in goaf and causes disasters was proposed. The research results explored the synergistic discharge mechanism during rock fracture process, and elucidated the enhancing effect of piezoelectric effect in rock fracture discharge process. The research can provide a theoretical basis for the disaster-causing mechanism in the process of roof fracturing caused by mine pressure in goaf.