循环动载冲击下加锚裂隙煤体力学响应试验研究

    Experimental study on mechanical response of anchored fractured coal under cyclic dynamic loading

    • 摘要: 为了解循环动载下加锚裂隙煤体的力学响应及破坏特征,采用分离式霍普金森压杆试验系统开展了循环冲击动载作用下加锚裂隙煤体动载冲击试验;分析了循环动载次数、动载冲击强度等因素对加锚裂隙煤体应力−应变曲线、锚杆轴力及宏观破坏的影响规律。研究结果表明:随着动载应变率的增加,锚固体试件强度增加,但随着动载冲击次数的增加,锚固体强度反而降低;冲击输入能量一定时,随着冲击次数的增加,煤体内部裂隙逐步扩展甚至破坏,锚杆对煤体扩展限制力降低;高能量冲击时,锚杆无法阻碍加锚裂隙煤体内部裂隙起裂与扩展,易发生加锚煤体整体瞬时破坏。

       

      Abstract: In order to understand the mechanical response and failure characteristics of anchored fractured coal body under cyclic dynamic load, the dynamic load impact test of anchored fractured coal under cyclic impact dynamic load was carried out by using the split Hopkinson pressure bar test system. The effects of cyclic dynamic load times and dynamic load impact strength on the stress-strain curves, bolt axial force and macroscopic failure of anchored fractured coal were analyzed. The results show that with the increase of dynamic load strain rate, the strength of anchorage specimen increases, but with the increase of dynamic load impact times, the strength of anchorage specimen decreases. When the impact input energy is constant, with the increase of impact times, the internal cracks of coal gradually expand or even fail, and the limiting force of bolt on coal expansion decreases. Under high energy impact, the bolt cannot hinder the initiation and expansion of the internal cracks in the anchored fractured coal body, and the overall instantaneous failure of the anchored coal body is prone to occur.

       

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