针对厚煤层掘进工作面底煤爆破断底卸压后仍发生冲击地压的现象, 以新疆硫磺沟煤矿厚煤层掘进工作面为工程背景, 采用现场调研、理论分析、数值模拟等方法, 对厚煤层掘进工作面强震动诱发底煤卸压失效机理进行研究。研究结果表明: 由于掘进导致围岩卸荷过程中煤体剪切破坏产生强烈震动, 震动波能量主要被松散底煤吸收, 最终导致底煤发生冲击; 提出了强震动诱发底煤卸压失效的能量判据, 基于此计算得到硫磺沟煤矿厚煤层掘进工作面底煤抛出高度${H_{text{c}}}$=1.26 m, 验证了理论分析的准确性, 同时得到卸压底煤冲击的临界震源能量$ {E_Z} $=13.7 kJ; 最后通过FLAC^3D模拟了不同震源能量对卸压底煤的扰动效应, 得到当震源总能量为22, 32, 42 kJ时, 底煤最大垂直速度分别为4.32, 6.91, 16.65 m/s, 底煤最大位移量分别为0.11, 0.57, 1.40 m; 底煤垂直速度随着震源总能量的增加不断增大, 随着动载作用时间的增加呈现先迅速增大后迅速减小最后衰减为零的趋势; 底煤位移随着震源总能量的增加而增大, 随着动载作用时间的增加其增大趋势逐渐变缓, 在动载作用时间为3/5个周期时达到最大值, 辅助验证了理论分析的准确性。

Rock burst still occurs after de-pressure blasting of bottom coal in the driving face of thick coal seam. Taking the driving face of thick coal seam in Liuhuanggou Coal Mine, Xinjiang, as the engineering background, the failure mechanism of bottom coal pressure relief induced by strong vibration in driving face of thick coal seam is studied by means of field investigation, theoretical analysis and numerical simulation. The results show that, due to the excavation, the coal body shear failure during the unloading process of the surrounding rock causes strong vibration, and the energy of the vibration wave is mainly absorbed by the loose bottom coal, which eventually leads to the impact of the bottom coal. The energy criterion for the failure of bottom coal pressure relief induced by strong vibration is proposed. Based on calculation, the height of bottom coal throwing ${H_{text{c}}}$ is determined to be 1.26 m in the heading face of the thick coal seam in the sulfur ditch, which verifies the accuracy of the theoretical analysis, and the critical source energy $ {E_Z} $ of 13.7 kJ the pressure relief bottom coal impact is obtained. Finally, the disturbance effect of different source energy on the pressure relief bottom coal is simulated by FLAC^3D, when the total energy of the source is 22, 32 and 42 kJ, the maximum vertical velocity of the bottom coal is 4.32, 6.91 and 16.65 m/s respectively, and the maximum vertical displacement of the bottom coal is 0.11, 0.57 and 1.40 m respectively. The vertical velocity of bottom coal increased with the increase of the total energy of the source. With the increase of the dynamic load time, it increased rapidly and then decreased rapidly and finally decayed to zero. The displacement of bottom coal increased with the increase of the total energy of the source, and the increasing trend gradually slowed down with the increase of the dynamic load time, and reached the maximum when the dynamic load time is 3/5 cycles, which assists in verifying the accuracy of the theoretical analysis.