Theoretical and experimental study of thermo electrical coupling mechanisms in coal bearing rocks

To reveal the mechanisms governing the temperature-dependent electrical behavior of coal-bearing surrounding rocks, a multi-physics coupling model was established and combined with experimental data to systematically analyze the evolution of resistivity and dielectric properties with temperature. The results show that resistivity undergoes a three-stage transformation: it first increases due to microcrack development and pore-water evaporation, then decreases sharply as carriers are thermally activated, and further declines at higher temperatures. Dielectric properties are markedly enhanced beyond a critical threshold, accompanied by a relaxation peak that indicates interfacial and ionic polarization dominate under thermal activation. A pronounced frequency dispersion is also observed, with polarization processes being suppressed at higher frequencies. These findings demonstrate that temperature strongly regulates carrier mobility and polarization capacity, thereby exerting a fundamental influence on the resistivity and dielectric response of rocks. This work provides theoretical support and practical reference for temperature correction in deep resource geophysical exploration, real-time monitoring of thermal damage in mines, and stability assessment of rocks under high-temperature conditions.