Dynamic monitoring of the mining-induced fractured zone in overburden strata, based on geo-electrical characteristics

Studies of the development height of mining-induced fractured zone in overburden strata are of great significance for safety and green mining of coal resources. Using geo-electrical response, a dynamic monitoring method for the fractured zone is investigated using the direct current resistivity method. Firstly, a numerical model of the mining-induced overburden is established and forward modeling is achieved from which the development of the caved zone and fractured zone is interpreted by inversion. The physical model then is designed, based on similarity theory and physical experiments, that displays visually dynamic deformation of the mining-induced overburden. After acquiring electrical data for the model, the inversion is done, based on which the development height of the fractured zone could be dynamically predicted. Finally, in order to prevent water inrush disasters, in situ investigations are carried out in one mine and height of the water-conducting fractured zone is determined. The researches show that the apparent resistivity inversion results, as the interpretation of caved zone and fractured zone, are approximately identical and the direct current resistivity method is proved to be an effective tool for dynamic monitoring of the mining-induced fractured zone.