Experimental Study of the Self-Potential Response Characteristics of Anisotropic Bituminous Coal during Deformation and Fracturing

The deformation and fracturing of coal rock is a crucial part of coal and rock dynamic disasters and is accompanied by variations in the electrical field of the rock. In this study, the self-potential characteristics of coal rock were measured to dynamically monitor the spatiotemporal evolution of coal rock deformation and fracturing. By using an MTS816 rock mechanics test system, an AE acoustic emission system and a self-developed SEMOS-LAB experimental system, synchronous measurements of the self-potential, stress and acoustic emission of anisotropic bituminous coal under uniaxial compression were obtained. The self-potential of anisotropic bituminous coal exhibited a good correspondence with the stress and acoustic emission counts during the damage and fracturing. As the stress gradually increased, the bedding-perpendicular coal samples exhibited a stronger linear relationship with the stress during initial loading than the bedding-parallel samples. The amplitude of the self-potential and stress of the bedding-perpendicular samples were higher than those of the bedding-parallel samples. Anisotropy is an important factor that affects the variation in the self-potential of a rock mass under loading. The results of this study can be applied to evaluate the stress state of coal by measuring its loading-induced electrical potential; thus, this work is important in the field for the monitoring and warning of coal and rock dynamic disasters.