Analysis of mining-induced fractures evolution in overburden about shallow seam based on simulation model test

On the basis of similar model test, the feasibility which mining-induced fractures evolution in overburden about shallow seam could be inversed by apparent resistivity method was discussed. The electric parameter changes in overlying strata during the course of deformation and failure and the relation between it and mining-induced fractures are canalized. The results show that apparent resistivity method can detect mining-induced fractures evolution in overlying strata about shallow seam. The isoline map of change rate in electrical resistivity could give expression to fracture development, so it can be the new division standard of the three failured strata zones. During mining active process in shallow seam, the range of fractured-zone in overlying strata is extended upward and forward, but it is imbalance in horizontal and vertical direction. The horizontal range is obviously larger than vertical, because the propagation of fractures is impeded by the thin bedrock. But once the thin bedrock is broken through by fractures, the upper rock or surface is instantly transfixion.