【摘要】 为探究循环载荷作用下组合煤岩体疲劳及损伤特性，基于RMT-150C试验系统，开展高静应力与小幅循环载荷组合作用下的疲劳破坏试验，研究不同应力幅值下岩-煤-岩组合煤岩体试样的疲劳及损伤特性，以及疲劳强度、滞回环特征、轴向应变、不可逆变形分别随循环次数的变化规律，揭示组合煤岩体疲劳损伤规律，分析疲劳破坏的主控因素。结果表明：组合煤岩体疲劳破坏受到静态加载作用下应力-应变的严格控制，疲劳破坏所需变形量应与上限应力对应的单轴压缩下应力-应变曲线峰后部分的变形量大致相当；组合煤岩体疲劳寿命随循环次数增加呈幂函数衰减，组合煤岩体疲劳上限应力比的门槛值约为0.8，应力门槛值约为22.5 MPa。疲劳试验过程中组合煤岩体的轴向应变、轴向不可逆应变及损伤度与随循环次数的变化规律基本相似，具体表现为：对于循环过程中未破坏的试样，存在初始加速及中后期等速2个阶段，而对于循环过程中破坏的试样，存在初始加速、中期等速及后期加速3个阶段；扰动幅值对组合煤岩体疲劳力学特性影响较大，增大扰动幅值会显著提高轴向应变、轴向不可逆应变及损伤度在中期等速阶段的增长速率，加快煤岩体损伤、劣化，大大缩短其疲劳寿命。更多还原

【Abstract】 In order to explore the fatigue and damage characteristics of combined coal and rock mass under cyclic loading, fatigue failure tests under the combined action of high static stress and small-amplitude cyclic loading were carried out based on the RMT-150C test system. The fatigue and damage characteristics of rock-coal-rock combined coal and rock mass specimens under different stress amplitudes, and the variation laws of fatigue strength, hysteresis loop characteristics, axial strain, irreversible deformation with the number of cycles were studied to reveal the fatigue damage law of combined coal and rock mass and analyze the main control factors of fatigue failure. The results show that the fatigue failure of combined coal and rock mass is strictly controlled by the stressstrain under static loading, and the deformation required for fatigue failure should be approximately equal to the deformation of the post-peak part of the uniaxial compression stress-strain curve corresponding to the upper limit stress. The fatigue life of combined coal and rock mass decreases exponentially with the increase of the number of cycles, and the threshold value of the fatigue upper limit stress ratio of combined coal and rock mass is about 0.8, and the stress threshold value is about 22.5 MPa. During the fatigue test, the variation laws of axial strain, axial irreversible strain and damage degree of combined coal and rock mass with the number of cycles are basically similar. Specifically, for specimens that have not failed during the cycle process, there are two stages: initial acceleration and middle and late stage constant speed. For specimens that have failed during the cycle process, there are three stages:initial acceleration, middle stage constant speed and late stage acceleration. The disturbance amplitude has a significant influence on the fatigue mechanical properties of combined coal and rock mass. Increasing the amplitude will significantly increase the growth rate of axial strain, axial irreversible strain and damage degree in the middle stage constant speed, accelerate the damage and deterioration of coal and rock mass, and greatly shorten its fatigue life.更多还原