Experimental research of surface potential of coal containing gas under cyclic loading

In order to research influence of gas on surface potential of coal containing gas under cyclic loading, an experimental system about surface potential of coal containing gas under cyclic loading was built. Characteristic laws of surface potential signals were tested and analyzed in coal destruction process by cyclic loading under different gas pressure, and mechanism of loaded destruction of coal containing gas was discussed. The experimental results show that coal containing gas can produce surface potential signal in loaded destruction process, and the surface potential signal has some relevance with stress and gas change. For the same type of coal samples, stress level under the maximum surface potential decreases as gas pressure increases. The surface potential signals obviously increases when stress is larger than the last maximum during cyclic loading.