煤矿软岩泥化巷道梯级强化控制原理与技术

Principle and technology of step strengthening control of soft rock argillization roadway in coal mine

  • 摘要: 煤系沉积岩层普遍泥性显著、富水性强、岩性软弱,软岩泥化巷道围岩稳定控制难题日益突显。以淮北矿区典型软岩泥化巷道为工程背景,根据工程地质条件调研与实测,分析了黏土矿物成分与宏细观破坏特征,明确了富水环境和应力环境是诱发泥质巷道变形破坏的重要因素,围岩泥化失稳体现为泥质岩体水化作用、锚固结构承载失效、围岩泥态垮冒渐进破坏模式,实现应力−渗水耦合作用下巷道围岩承载结构稳定控制起到决定性作用;在此基础上提出了软岩泥化巷道梯级强化控制原理,即在保障“支护−围岩”相互作用关系中高预紧力、高刚度、高强度锚杆(索)支护承载闭环结构的前提下,根据泥岩水化程度判断工程失稳控制方法,形成了锚注一体泥质围岩性质改良、旋喷注浆浅表桩群结构强化、逐层锚喷泥化岩体强力置换3项重要技术路径;于芦岭煤矿西轨大巷应用了自主研发的矿用新型多钢绞线组合中空注浆锚索束进行底鼓治理,首次在涡北煤矿8204机巷开展了井下高压旋喷注浆工程实践,采用了人工构筑岩体强力置换泥态围岩的方式解决了朱仙庄矿Ⅱ水平第二皮带大巷泥化围岩失稳难题,巷道围岩变形量、支护围岩成型情况与钻孔窥视结果表明,研究成果较好地解决了软岩泥化巷道控制问题,多层次强化了泥质巷道围岩承载能力,保障了围岩长期安全稳定,为软岩泥化巷道围岩控制提供了有效的科学控制理念与技术支撑。

     

    Abstract: The sedimentary rock strata of the coal measure are generally characterised by significant argillity, high water content and weak lithology. The problem of controlling the stability of the surrounding rock in soft rock argillation roadways has become increasingly prominent. Taking the typical soft rock argillation roadway in Huaibei Mining area as the engineering background, based on the investigation and measurement of engineering geological conditions, the composition of clay minerals and the macro and micro failure characteristics are analyzed, and it is clear that the water-rich environment and stress environment are the important factors inducing the deformation and failure of argillation roadway. The mudification instability of surrounding rock is mainly reflected in the progressive failure mode of hydration of argillous rock mass, bearing failure of anchorage structure, and mud-state collapse of surrounding rock. It plays a decisive role to realize the stability control of bearing structure of surrounding rock in roadway under the coupling effect of stress-water. On this basis, the step strengthening control principle of soft rock argillation roadway is put forward. On the premise of ensuring the closed-loop structure with high preload, high stiffness and high strength anchor (cable) support in the interaction relationship between support and surrounding rock, the engineering instability control method is judged according to the hydration degree of mudstone. Three important technical paths have been formed to improve the properties of mudstone surrounding rock with anchor injection, strengthen the structure of shallow pile group with rotary grouting, and replace the mudstone mass with anchor injection layer by layer. The new multi-strand combined hollow grouting anchor cable bundle independently developed for mining is applied to the floor heave control in the west roadway of Luling Coal Mine. For the first time, the underground high pressure rotary-grouting engineering practice was carried out in the 8204 roadway of Guobei Coal Mine. The instability problem of mudded surrounding rock in belt roadway of the second level of Zhuxianzhuang Coal Mine is solved by the method of strong displacement of mudded surrounding rock by artificial constructed rock mass. According to the deformation of surrounding rock of roadway, the supporting forming condition of surrounding rock and drilling into results show that the results better solve the problem of soft rock roadway control. It strengthens the bearing capacity of surrounding rock of muddy roadway at multiple levels, ensures the long-term safety and stability of surrounding rock, and provides effective scientific control concept and technical support for surrounding rock control of soft rock argillation roadway.

     

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