Study of the vibration frequency characteristics of tectonic coal containing assemblages at different loading rates

To reduce the vibration frequency superimposed on the original vibration frequency of a coal seam containing structural coal, damage to the coal structure should be reduced, and the occurrence of coal and natural gas outburst accidents should be prevented. Therefore, the influence of different loading rates on the vibration frequency of structural coal assemblages is studied. In this paper, an HG-01 equipment vibration frequency test system is used, and the percussion method is used to determine the influence of different structural coal ratios on the inherent vibration frequency of the combined sample. The self-developed integrated experimental bench of high- and low-frequency impact mechanics and frequency comprehensive testing is used to load the sample and test the vibration frequency of the sample containing tectonic coal combinations at various loading rates. The results show that the vibration frequency of the combined samples containing tectonic coal gradually increases, whereas the average value of the amplitude gradually decreases as the loading rate increases. During the vibration of a tectonic coal assembly, the amplitude of vibration is related to its intrinsic vibration frequency. When an external force or pressure is applied to the tectonic coal assembly at a frequency close to the natural frequency, resonance is reached, and then the amplitude of vibration increases. However, if the applied loading rate causes the vibration frequency of the coal body to exceed the resonance frequency, the tectonic coal assembly will not have enough time to respond to the change in the external pressure. At this point, the vibration amplitude decreases. Studying the vibration frequency characteristics of samples containing tectonic coal assemblages at various loading rates can offer basic theoretical support for the gas transportation law of coal seams and guide gas extraction and prevention of mine gas accidents.