Seismoelectric Response to a Point Source During Coal Seam Excavation

Advanced detection is an important subject in roadway excavation in coal mining. The mostly used methods include the seismic, electric, and electromagnetic (EM) evaluations, which are independently treated. Due to the existence of the electrokinetic effect in the underground rocks, the seismic and EM waves can be coupled, resulting in the well-known seismoelectric conversion, which would be useful for advance detection of anomalous body. In this study, we investigate the seismoelectric signals generated during the coal-mining process. We use the COMSOL software to establish the computational model and solve the frequency-domain response of the seismoelectric waves excited by a point force source. The time-domain waveforms of seismoelectric waves are obtained by the fast Fourier transformation. We simulate the seismoelectric waves in the models containing collapsed column and intrusive body. The results show that the seismic waves can generate interfacial seismoelectric waves at the boundaries of the collapsed column. The seismoelectric waves contain the information of collapsed column, including its width and conductivity as well as its distance from the heading face. The simulations of the intrusive body model show that the seismic waves can excite seismoelectric waves at the interface of the intrusive body. The numerical results suggest a potential of the seismoelectric waves in advance detection in coal mining.