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为研究单向应力状态下周期荷载对煤疲劳破坏特性的影响,利用MTS815.02岩石力学试验系统进行了多级周期荷载试验.试验结果表明:(1)当周期荷载峰值应力低于煤样疲劳强度时,煤样变形具有初始和停滞两个发展阶段,耗散能呈L型演化规律;当周期荷载峰值应力超过煤样疲劳强度时,煤样变形具有初始、等速和加速3个发展阶段,耗散能呈U型演化规律;(2)对于煤样的疲劳破坏,环向变形和体积变形比轴向变形更为敏感;(3)常规单轴压缩试验时,煤样大致呈单斜面剪切破坏,局部伴随拉伸破坏;周期荷载试验时,煤样破坏后产生许多小碎块,偶尔可见较大块体;(4)只有当周期荷载峰值应力高于煤样的疲劳强度时,煤样内部微裂隙才开始大量萌生、扩展、贯通,这一过程将最终导致煤样发生疲劳破坏.“,”To research the coal's fatigue failure characteristics under uniaxial state,the multi-level amplitude cyclic loading tests were conducted using MTS815.02 rock mechanics test system.The results show that:(1) When the peak stress of cyclic loading is less than the coal's fatigue strength,the coal's deformation exhibits the two phases:namely,primary and stagnation phases,and the dissipated energy curve is L-shaped.However,when the peak stress of cyclic loading exceeds the coal's fatigue strength,the coal's deformation exhibits the three phases:namely,primary,steady,and acceleration phases,and the dissipated energy curve is U-shaped;(2)Compared with the axial deformation,the circumferential and volumetric deformations are more sensitive to coal's fatigue failure;(3) Coal sample mainly fails in the mode of a single inclined shear plane and accompanied by tensile failure in conventional uniaxial compression test.However,coal sample is mainly destroyed into many small fragments and sometimes accompanied by few large blocks in cyclic loading test;(4) Only when the peak stress of cyclic loading exceeds the coal's fatigue strength,the micro-cracks inside coal begin to massively initiate and propagate,and eventually result in the coal's fatigue failure.