胀锁型锚索双向加固窄煤柱试验研究与工程应用

Bidirectional reinforcement of narrow pillar with inflatable lock-type anchor experimental investigation and its application

  • 摘要: 针对沿空掘巷窄煤柱非对称变形问题,提出了对穿锚索双向加固窄煤柱技术,设计了伸长型和胀锁型两种对穿锚索结构及工艺,开展了对穿锚索拉拔试验,试验表明两种锚索结构均满足抗拉要求,从锚索破坏形态、施工便捷性和材料经济性等方面对比分析,确定胀锁型对穿锚索为窄煤柱双向加固的首选。进一步通过相似模型试验与数值模拟研究了不同加固方式下煤柱承载变形规律和对穿锚索受力特征。结果表明:双排紧密型对穿锚索加固试件较未加固试件峰值荷载提高了96.04%,且随着锚索排数及数量的增加,窄煤柱双向加固稳定性越来越高,胀锁型对穿锚索提高了煤柱破坏前的能量储存量和临界破坏点。最后,在济宁三号煤矿12304工作面运输巷开展胀锁式对穿锚索加固窄煤柱工程试验,监测显示对穿锚索锚固力超过220 kN,锚索加固区煤柱帮鼓量降低70%,窄煤柱整体稳定性好,窄煤柱双向加固技术可行,为沿空掘巷工程提供了新技术途径。

     

    Abstract: This study targets at asymmetric deformation of narrow coal pillar in gob-side entry driving.We put forward the bidirectional reinforcement of narrow pillar with opposite-crossing anchor cable.Specifically, we designed two types of anchor cable structure: the byelongation type and the expansion lock type, and carried out the pull-out test of opposite-crossing anchor cable, the test shows that both anchor cable structures could meet the tensile requirements.We conducted comparative analysis on the morphology of anchor cable failure, construction convenience and the economic aspect of material selection, where the expansion lock type crossed anchor was selected for narrow coal pillar bidirectional reinforcement.Furthermore, we investigated the bearing deformation patterns of coal pillars and the stress characteristics of anchor cables under different reinforcement methods through similar model tests and numerical simulation.Results show a 96.04% increase of peak load in the specimen reinforced by the double-row tight opposite-crossing anchor cable compared with that of the not reinforced specimen, and higher stability of the narrow pillar reinforced by the double-row tight opposite-crossing anchor cable as the rows of the anchor cable increases in number.The expansion lock anchor type crossed cable improved the energy storage and the critical failure point before the coal pillar was destroyed.Finally, the engineering test of expansive lock type crossed anchor cable to reinforcing narrow coal pillar was carried out in the transportation roadway of 123 lower 04 working face of Jining No.3 Coal Mine.The monitoring show that the anchoring force of the anchor cable exceeded 220kN, with 70& reduction of the coal pillar in the reinforcement area and good overall stability of the narrow coal pillar.It proves the feasibility of the bidirectional reinforcement technology of narrow pillar and provides new technical way for gob-side entry driving.

     

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