Study on EP response to compression-induced damage of coal-measure rock and the mechanism behind such response

• Published in: Journal of geophysics and engineering 2019-02, Vol.16 (1), p.242-252
• Main Authors: Niu, Yue, Song, Xiaoyan, Li, Zhonghui, Wang, Enyuan, Zhang, Xin, Wang, Mingfu, Dong, Mingfu
• Format: Article
• Language: English
• ISSN: 1742-2132; 1742-2140
• DOI: 10.1093/jge/gxz002

Abstract Coal-measure rock plays the main role in coal rock control. To study the characteristics of the electric potential (EP) response and its mechanism under load, a uniaxial compression experiment on coal-measure rock was carried out. The results indicate the following. (1) Notable EP signals are produced during the process, which are associated with the loading levels and damage states of coal-measure rock. With an increase of loading level, EP intensity increases accordingly. When an abrupt change occurs, an abrupt change of EP also occurs, especially for the sample failing. (2) The statistical analysis shows that the sequential response of EP intensity is closely related to the loading process. The correlation coefficient is significantly correlated, and even highly correlated, between EP and load. Furthermore, the time series of the EP data follows the R/S variation rule with a Hurst exponent of up to 0.916. (3) Under the action of stress, the generation and expansion of fractures cause the damage and destruction of coal-measure rock. Charge separation and electron emission are the principal mechanisms of EP response. EP response characteristics carry the information of the loading level and the state of the damage of such rock, which is expected to detect the stability and reflect the evolution of the damage.