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卸压钻孔对锚索作用的影响及控制方法研究

Study on the effect and control of the pressure relief borehole on anchor cable

  • 摘要: 钻孔卸压是冲击地压巷道防冲的重要手段,但卸压钻孔会对巷道围岩体产生破坏,进而影响支护环境。为研究卸压钻孔对巷道支护的影响,基于锚索受力在线监测系统对冲击地压巷道锚索在钻孔卸压后的受力进行监测,并通过数值软件3DEC对锚索受力情况进行模拟。结果表明:随掘进工作面推进,锚索受力初期均出现锯齿震荡式增长,并最终呈现缓慢平稳式增长;安装锚索后推进20 m,3根锚索受力均有明显增加,越靠近掘进工作面,锚索载荷增加幅度越大;施工卸压钻孔前后锚索受力变化较小,其中孔口部分略有下降;卸压钻孔对围岩整体塑性区影响不大,仅在孔壁形成部分零散塑性屈服点;在卸压钻孔孔口2 m内采用囊袋式封孔器进行充填,能较好解决卸压钻孔对锚网支护的影响。

     

    Abstract: Borehole pressure relief is an important means of shock resistance for rockburst roadways, but the boreholes will damage the roadway surrounding rock and affect the supporting environment. In order to study the influence of pressure relief boreholes on roadway support, based on the on-line monitoring system, the anchor cable stress after drilling pressure relief is monitored, and the anchor cable stress is simulated by 3DEC. The results show that with the advance of heading face, the anchor cable stress increases in sawtooth vibration at the initial stage, and finally increases slowly and steadily; when the heading face advances 20 m after installing anchor cable, the stress of the 3 anchor cables increases obviously, the closer to the heading face, the greater the increase of the anchor cable stress; compared with that before construction of pressure relief boreholes, the change of anchor cable stress after construction pressure relief boreholes is small, and the orifice part decreases slightly; pressure relief boreholes have little effect on plastic zone of surrounding rock, and only some scattered plastic yield points are formed on the hole wall; the influence of pressure relief boreholes on bolt mesh support can be better solved by filling with bag hole sealer within 2 m of the orifice of pressure relief borehole.

     

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