ZHAO Liang, ZHAO Yaojiang, GUO Shengliang, CHEN Chunjian, PAN Yuting, WANG Hao. Experimental study on mechanical and acoustic emission characteristics of raw coal and briquette after high temperature action[J]. CHINA MINING MAGAZINE, 2020, 29(12): 206-211. DOI: 10.12075/j.issn.1004-4051.2020.12.010
    Citation: ZHAO Liang, ZHAO Yaojiang, GUO Shengliang, CHEN Chunjian, PAN Yuting, WANG Hao. Experimental study on mechanical and acoustic emission characteristics of raw coal and briquette after high temperature action[J]. CHINA MINING MAGAZINE, 2020, 29(12): 206-211. DOI: 10.12075/j.issn.1004-4051.2020.12.010

    Experimental study on mechanical and acoustic emission characteristics of raw coal and briquette after high temperature action

    • Uniaxial compression acoustic emission(AE) tests were carried out on coal samples using uniaxial compression test instruments and AE detection system.The effects of temperature on mechanics and AE characteristics of raw coal and briquette were analyzed.The results show that the peak strength of briquette is higher than that of raw coal at the same temperature.With the increase of test temperature, the peak strength and damage strength of raw coal decrease gradually, and the peak strain also decreases, but the peak strength of briquette increases gradually, and the damage strength of briquette after high temperature treatment is lower than that at normal temperature.By analyzing the AE characteristics of coal samples at different stages, the mechanical properties of raw coal and briquette at the same temperature coincide with the characteristics.There is a “blank period” in the initial stage of loading of raw coal.With the increase of test temperature, the maximum AE counts of raw coal increase, reach the maximum at 200 ℃, the maximum AE counts of briquette increase first and then decrease, and reach the maximum at 100 ℃.Near the inflection point of stress-time curve, the AE counts of coal samples are active and the raw coal is stimulated.The increase phenomenon is obvious, and the inflection point moves forward after high temperature treatment compared with normal temperature coal sample.The difference of AE signals between raw coal and briquette during loading indirectly indicates the difference of their structures.Compared with the difference of their laws after high temperature action, the difference of thermal stress produced after high temperature action on the internal knot of coal sample is more obvious.The severity of structural damage.The appearance of inflexion point and the sharp increase of AE signal after high temperature treatment of raw coal and briquette indicate the large area of internal cracks in coal and rock.Therefore, preventive measures can be taken in time for possible dynamic disasters in coal mines.
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