Coupled stress–apparent resistivity model for rock deformation and failure based on experimental analysis

The key to preventing mine water disasters and gas hazards lies in monitoring the development of mining–induced fractures in the roof strata of coal seams. Although the borehole resistivity method (BRM) is an advanced technology, its effectiveness is limited by the incomplete understanding of how the apparent resistivity of rock varies during the development of mining-induced fractures and the difficulty in quantitatively analyzing the extent of fracture development. This study used experimental analysis to identify the patterns governing the apparent resistivity changes of rock throughout the development of mining-induced fractures under different confining pressure levels and to formulate a quantitative model for assessing rock fracture development. The study examined stress and the apparent resistivity of five rock types under three confining pressure levels. The results reveal that the relationship between stress and apparent resistivity in loaded rocks is characterized by distinct stage–dependent variations. Specifically, during the microcrack closure stage, there is a negative linear correlation between the apparent resistivity of the rock and stress. In the linear elastic stage, the apparent resistivity of identical rocks remains stable and consistent across varying confining pressure levels. Conversely, in the stable crack propagation and failure stages, a positive linear correlation is observed between the apparent resistivity of the rock and stress. Utilizing experimental data, a coupled stress–apparent resistivity model for rock deformation and failure (CSAR model) was developed. This study not only improves the precision of BRM in monitoring mining-induced fracture development in coal seam roof strata but also tackles the challenges of quantitatively analyzing the extent of fracture development. • A novel testing system for simultaneously measuring stress, strain, and apparent resistivity of rocks under different confining pressure levels is developed. • The patterns governing changes in apparent resistivity during rock deformation and failure are revealed, and a rational explanation is provided by integrating these patterns with the development process of rock fractures. • A coupled stress–apparent resistivity model for rock deformation and failure is developed, enabling the quantitative analysis of rock fracture development.