The 4th International Symposium on Mine Safety Science and Engineering (ISMSSE2018)

318 / 2018-05-04 13:51:04

Experimental study on multi-parameter electrical characteristics of coal containing gas during extrusion process

gas-containing coal, extrusion, evolution process, resistivity, characteristic parameters

Gas of Coal Mine & Coal and Gas Outburst > Coal and gas outburst

In this paper, a stress-oriented experiment of gas-containing coal extrusion was performed by establishing an experimental system integrating gas injection, loading and electrical testing. Then, the apparent resistivity images in different stages of evolution process of gas-containing coal extrusion were obtained. Finally, multi-parameter electrical characteristic parameters were extracted, and the variation and characterization significance of characteristic parameters were analyzed. The results show that the overall resistivity values of the apparent resistivity image decrease in the gas adsorption equilibrium stage and the stress loading stage. After the extrusion occurs, the apparent resistivity rises remarkably; in addition, there exist abnormal resistance values in some areas, which is consistent with the distribution of coal fractures. The fundamental reason for this phenomenon lies in the changed conductive channel of gas-containing coal. Moreover, average and maximum values of apparent resistivity of coal both decrease first and then increase, whereas the current and spontaneous potential both rise first and then fall, of which the change of current is more obvious. These changes, which characterize the evolution process of gas-containing coal extrusion, can provide theoretical guidance and experimental basis for geophysical exploration of gas dynamic disasters in coal and rock.