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为进一步改善瓦斯爆破抽放效果,分析煤体爆炸应力波作用损伤过程与机理,设计并完成模拟煤体爆炸应力波损伤累积试验。测试试块的超声波波速并计算损伤值。分析爆炸应力波作用下煤体损伤累积过程与规律。结果表明,煤体爆炸应力波损伤是爆炸应力波直接压缩和拉伸作用以及间接扰动作用的结果。随着爆炸应力波作用次数的增加,煤体损伤持续增加,近区测点损伤值在较高阈值内快速增加,中远区测点损伤初期在较低阈值内缓慢增加,后期随着累积效应的增强损伤快速增加;近区测点累积损伤随与炮孔中心距离的增大而快速衰减,中远区累积损伤缓慢减小;煤体强度等力学参数大幅度劣化,宏观裂纹形成后,煤体将在较低损伤值条件下发生断裂破坏。
In order to further improve the gas drainage effect, the damage process and mechanism of the coal blasting stress wave were analyzed. The cumulative stress wave damage simulation experiment was designed and completed. Test the ultrasonic wave velocity test block and calculate the damage value. Analysis of the process and laws of damage accumulation in coal under explosive stress wave. The results show that the stress wave damage of coal body is the result of the direct compressive and tensile effects of the stress wave and the indirect disturbance. With the increase of the number of explosion stress waves, the damage of coal body continued to increase. The damage value of the near-field measurement point increased rapidly within a relatively high threshold. In the early and middle stages, the damage point of the measurement point increased slowly within the lower threshold. With the cumulative effect The cumulative damage rapidly increases with the increase of the distance from the center of the borehole, the cumulative damage in the long-term zone decreases slowly; the mechanical parameters such as the strength of the coal body greatly deteriorate; after the formation of the macro-crack, Fracture damage occurs at lower damage values.