Mining Institute,Liaoning Technical University,Fuxin　 123000,China

以钻孔卸压原理及分布式光纤传感技术为基础,建立了卸压钻孔周边煤体内部应变感测模型,提出了以光纤拉伸应变值及卸压半径为指标的卸压效果评价方法。通过对传感光缆下方钻孔卸压周边煤体内部应变定期测试,并结合钻孔内部表观现象观测,根据不同时间钻孔周围煤体内部应变及表观破坏特征将钻孔卸压过程分为裂隙发育阶段、极限平衡阶段、塌孔阶段、破碎煤体压实阶段等四个阶段。分别确定了在忻州窑矿地质及开采条件下钻孔卸压过程中各阶段的时间区间,得出超前94~101 m以上施工钻孔,其卸压效果较为显著。利用微震监测系统,对比分析了卸压钻孔施工时间调整前后的微震事件分布特征,结果表明:当卸压钻孔施工达到超前工作110 m后,工作面周边高能量事件的频次明显减少、微震事件平均能量明显降低38%。

Based on the principle of borehole pressure relief and distributed optical fiber sensing technology,the inter- nal strain sensing model of coal around the pressure relief boreholes was established. Also,the paper proposed a meth- od of evaluating the pressure relief effect with the optical fiber tensile strain value and the radius of yielded zone. Bore- holes are drilled under the sensing cable,and the internal strain of the surrounding coal can be tested periodically. Combined with internal phenomena observation,the borehole pressure relief process can be divided into four stages,ac- cording to the characteristics of internal strain and apparent failure of coal in different times. The four stages are re- spectively fissure development stage,limit equilibrium stage,collapse hole stage,and broken coal compaction stage. The method was used to determine the time interval of each stage in the process of borehole pressure relief under the geological conditions of Xinzhouyao Coal Mine,and concluded that the pressure relief effect of construction drilling a- bove 94 to 101 m was more significant. The distribution characteristics of micro-seismic events before and after the construction time adjustment of pressure relief boreholes were analyzed by micro-seismic monitoring system. The results show that the frequency of high-energy events around the No. 8939 panel is significantly reduced,and the average en- ergy of the micro-seismic event is significantly reduced by 38% .

LI Yunpeng,ZHANG Hongwei,HAN Jun,et al. Time effect of borehole pressure relief based on distributed optical fiber sensing technology [J]. Journal of China Coal Society,2017,42(11):2834-2841.