Due to the extensive excavation of open-pit coal mines in northwest of China, the rock slopes formed by special environments are subjected to freeze-thaw (F-T) action, which has a certain impact on their stabilities. In order to evaluate the mechanical properties and micro damage characteristics of coal under different freeze-thaw cycles, uniaxial compression experiments combining acoustic emission tests were conducted. The results suggest that as the number of freeze-thaw cycles increased, elastic modulus of coal samples decreased, the samples showed ductile damage characteristics and initial compaction stage gradually increased. Compared with unfrozen-thawed coal sample, the compressive strength of the coal samples decreased by 23.27% after 10 F-T cycles, 31.06% after 15 F-T cycles, and 36.01% after 20 F-T cycles. The internal fissures in the coal samples transitioned from tensile fissures to shearing fissures, and the samples gradually showed tensile-shear combined failure. The final cumulative energy of the coal sample became lower, the cumulative energy duration increased and the time point of the energy surge was delayed with the increase of cyclic freeze-thaw times. A damage model based on the evolution law of the cumulative energy was established to bridge the gap between macro-micro damage mechanics.

由于我国西北地区露天煤矿的大面积开挖，特殊环境形成的岩质边坡受到冻融（FT）作用，对其稳定性产生一定影响。为评价煤在不同冻融循环下的力学性能和微损伤特性，结合声发射试验进行了单轴压缩实验。结果表明，随着冻融循环次数的增加，煤样的弹性模量降低，煤样呈现韧性破坏特征，初始压实阶段逐渐增加。与未冻融煤样相比，10个FT循环后煤样的抗压强度下降了23.27%，15个FT循环后下降了31.06%，20个FT循环后下降了36.01%。煤样内部裂隙由拉伸裂隙向剪切裂隙转变，试样逐渐呈现拉剪复合破坏。随着循环冻融次数的增加，煤样的最终累积能量变低，累积能量持续时间增加，能量激增的时间点延迟。建立了基于累积能量演化规律的损伤模型，弥合了宏观和微观损伤力学之间的差距。