The fatigue damage of rock is an important factor affecting the stability of rock structure. In this paper, the mechanical response of\ncoal under cyclic loading was studied. In order to accurately describe the deformation characteristics of coal under cyclic loading,\nan elastic-plastic model of coal based on the theory of subloading surface was established and verified by experiments. The model\ncan well reflect the Mancin effect and ratcheting effect of coal samples, which is basically consistent with the actual deformation\ncharacteristics of coal, and the theoretical value and experimental value are in good agreement. At the same time, the cyclic\nresponse characteristics of specimens under strain load disturbance were analyzed. The results show that the specific strain\ndisturbance can only cause a certain damage to coal and the area of hysteresis loop decreases first, then stabilizes, and then\nincreases as the number of cycles increases. In addition, the damage factor Dn in the model was analyzed in this paper. Dn, which\ncan accurately describe the damage process of coal, accurately locate the time point of disturbance load change, and has greater\nsensitivity to coal failure, is helpful to improve the accuracy of the stability judgment of coal structure and ensure the safety of\nengineering. The above results are of great significance for strengthening the understanding of coal mass instability process and\nmode under cyclic loading.
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