三硬条件下孤岛区域大直径钻孔防冲方案优化

Research on optimizing large diameter drilling scheme of rockburst prevention in isolated area under three hard conditions

忻州窑矿是典型的冲击地压矿井,为确保忻州窑矿8939三硬条件孤岛工作面安全高效回采,采用理论计算的方法,得出在该地质条件下卸压钻孔参数的合理范围,并采用数值模拟方法对理论计算得出的参数范围进行深入研究,得出适合该地质条件下的大直径卸压钻孔优化方案。采用KBD5电磁辐射仪对卸压效果进行了检验,结果表明,经过优化,煤体内电磁辐射强度较原卸压方案降低了15.7%,累计脉冲数降低了16.6%。方案优化后不但提升了卸压效果,而且节省了约690个钻孔和30%的工作量。

Xinzhouyao Coal Mine is a typical rockburst mine,which is located in Datong Mining Area. Panel 8939 is an isolated panel which owes hard roof,hard coal and hard floor（ it is referred to as＂three hard＂）. In order to ensure panel 8939 mining safe and efficient,the paper used theoretical calculation to obtain reasonable drilling parameters under the special geological condition. The research result shows that the interval of drillings should be ranged from 0. 5 m to 0. 8 m and the length of drillings should be more than 9. 06 m when the diameter of drillings is 108 mm.The authors uses numerical simulation method to further determine the drilling parameters and formulate optimized scheme which is suitable for the geological conditions. The interval of drillings is expanded from 0. 5 m to 0. 7 m,and the length of drillings increased from 8 m to 12 m. The stress concentration phenomenon of coal pillar between panel 8939 and panel 8937 is remarkable. The stress value reached the range from 24. 0 MPa to27. 0 MPa and the stress concentration factor reached the range from 2. 5 to 2. 9. The stress peak value of coal pillars decreased from 23. 6 MPa to 16. 0 MPa,and the stress reduced 32. 3%.The peak value point is far away from the roadway 12 m to 13 m,which is 5 m deeper than before. The pressure relief effect of the electromagnetic radiation instrument is tested by the model of KBD5. Then the authors uses electromagnetic radiation instrument whose model is KBD5 to test the effect of pressure relief.The results show that the average intensity of electromagnetic radiation reduced 15. 7% and cumulative pulse number reduced16. 6% after constructing optimization drillings. The scheme not only enhanced the effect of drilling,but also saved about 690 drillings,and the workloads can decrease about 30%. It provides good guarantee for panel 8939 to mining safe and efficient. The achievements can provide reference and basis for preventing and controlling rockburst in similar conditions.