Abstract：To systematically investigate the evolution patterns and intrinsic relationships between the micro-mesoscopic structure and macroscopic mechanical properties of open-pit mine mudstone under varying temperatures, samples from an open-pit mine in Inner Mongolia were subjected to heat treatment at temperatures ranging from 25 °C to 600 °C. Multiscale characterization techniques, including X-ray diffraction (XRD), computed tomography (CT) scanning, and scanning electron microscopy (SEM), were employed to analyze the evolution of mineral composition, crystallinity, pore structure, and microcrack distribution. In conjunction with uniaxial and triaxial compression tests, the influence of temperature on mechanical parameters such as strength, elastic modulus, and Poisson’s ratio was examined, elucidating the restraining effect of confining pressure on high-temperature damage. The main findings are as follows: (1) While mineral composition remained relatively stable, crystallinity demonstrated a nonlinear trend, initially increasing and then decreasing, with a peak of 77.9% observed at 400 °C. (2) Porosity increased from 6.8% to 17.9% with rising temperature, as the pore structure evolved from smaller to larger pore sizes; additionally, microcracks initiated, propagated, and interconnected, ultimately forming a highly connected three-dimensional fracture network at 600 °C. (3) High-temperature exposure shifted the failure mode from ductile to brittle. The peak strength under uniaxial compression and crystallinity exhibited a consistent trend with temperature variation, indicating that microstructural evolution is a key factor governing macroscopic mechanical behavior. (4) Under varying confining pressures, both peak strength and elastic modulus of mudstone increased with rising temperature, while the effectiveness of confining pressure in mitigating thermal damage improved with increased confining pressure. This finding suggests that confining pressure can inhibit the propagation of microcracks and partially offset the thermal damage caused by high temperatures. The research results provide a crucial basis for developing slope control measures in open-pit coal mines under conditions of spontaneous coal combustion.
李广贺1，2*，刘赛飞1，王 东1，贾宏君1，王来贵3，孔令伟4. 不同温度下露天煤矿泥岩多尺度特征研究[J]. 岩石力学与工程学报, 2026, 45(8): 2283-2298.
LI Guanghe1, 2*, LIU Saifei1, WANG Dong1, JIA Hongjun1, WANG Laigui3, KONG Lingwei4. Multiscale characterization of mudstone in open-pit coal mines under thermal effects. , 2026, 45(8): 2283-2298.
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2026, Vol. 45 
