在深埋中等坚硬煤层采掘工作面煤壁片帮大多表现出明显时滞性,针对采掘工作面煤壁片帮发生时滞性应力特征,在RMT-150B岩石力学试验系统上进行煤样单轴压缩和分级加载对比试验,分析两种加载方式下煤样时滞性变形破坏特征,结果表明:两种加载方式在煤样峰值前应力-应变曲线宏观没有明显区别,单轴压缩峰值后出现分次应力跌落,而分级加载最后一级应力高于煤样屈服强度时没有明显峰值点,出现屈服平台,峰值后应力跌落迅速;单轴压缩得到的力学参数明显高于分级加载试验值,表现出煤样的力学参数具有时滞性;分级加载应力比低于70%时,煤样轴向和环向变形特征不明显,分级加载应力比高于70%时,尽管轴向应力保持恒定,随着时间延长煤样轴向和环向变形则不断增加,且环向应变远大于轴向应变,体积不断增加,在此期间,煤样继续吸收外界能量内部材料逐步损伤破坏,新生微裂纹不断演化、发展和汇聚,分级加载应力水平比越高,延时破坏越短,相反延时破坏则越长,分级加载时表现出明显时滞性特征;单轴压缩时煤样破坏相对简单,具有明显张剪性双重破裂面,而分级加载时煤样破碎充分,破坏形式复杂,环向膨胀特征明显,与采掘工作面煤壁延时片帮破坏特征极为相似。其研究结果对采掘工作面煤壁延时片帮治理具有一定的参考意义。 Most of the coal wall slices in the mining face of the medium-hard coal seam show obvious time-delay. In view of the time-lag stress characteristics of the coal wall slice in the mining face, the coal-sample uniaxial Compressive and graded loading comparison tests were carried out to analyze the time-dependent deformation and failure characteristics of the coal samples under the two loading methods. The results show that there is no significant difference between the two loading methods in the macroscopic stress-strain curve of the coal samples, And the stress at the last stage of grading and loading is higher than that at the yield strength of coal sample. There is no obvious peak point and the yielding platform appears, and the stress drops rapidly after the peak stress. The mechanical parameters obtained by uniaxial compression are obviously higher than the graded and loaded test values, The mechanical parameters of the coal samples are time-lagged. The axial and circumferential deformation characteristics of the coal samples are not obvious when the staged loading stress ratio is less than 70%. While the staged loading stress ratio is higher than 70%, although the axial stress remains constant, As the time prolongs, the axial and circumferential deformation of coal sample increases continuously, and the circumferential strain is far greater than the axial strain and the volume increases continuously. During this period, the coal sample continues to absorb the external energy. The damage and destruction of newborn microcracks evolve, develop and converge. The higher the stratum-to-stratum stress level ratio, the shorter the delay damage, and the longer the delay damage is, the longer the staged loading is. The coal sample damage is relatively simple, with obvious double shearing surface, while the coal sample is fully crushed, the destruction form is complex and the annular expansion characteristics are obvious. It is very similar to the failure characteristics of the coal wall time-lapse chip mining. The results of this study have certain reference value for the coal gangway slagging processing for mining face.