深埋复合顶板煤巷离层失稳机理及控制研究

Study on mechanism and control of separation instability in deep-buried composite roof coal roadway

为探究深埋复合顶板煤巷离层失稳及控制机理,以淮南某矿1692(1)运输顺槽为工程背景,原位观测并分析巷道顶板变形破坏特征及原支护效果,基于材料力学原理建立复合顶板岩层力学模型,解析复合顶板各分层挠度表达式,揭示复合顶板离层失稳机理,并探究全长锚固和锚索对复合顶板离层控制机理,提出全锚改性-长锚索组合联合支护技术。研究结果表明:联合支护利用全长锚固增加复合顶板底层的弹性模量,使复合顶板底层挠度下降,通过锚索将复合顶板各分层组合成整体,形成组合梁结构,使复合顶板整体挠度降低,现场监测表明顶底板移近量下降64%,顶板未发现离层现象,最大裂隙深度由8.1 m降低至3.8 m,降低53.80%,煤巷的稳定性得到显著提升。研究结果可为深埋复合顶板离层垮落失稳控制提供借鉴。

To explore the separation instability and control mechanism of deep-buried composite roof coal roadway,taking the 1692(1)transport roadway in a mine in Huainan as the engineering background,the deformation and failure characteristics of the roadway roof were observed in situ and analyzed,and the original support effect was analyzed.Based on the principles of material mechanics,a mechanical model of the composite roof rock layers was established,and the expressions for the deflection of each layer of the composite roof were analyzed.The mechanism of separation instability of the composite roof was revealed,then the control mechanism of full-length anchorage and anchor cables on the separation of composite roof was explored,and the joint support technology of full-length anchorage modification combined with long anchor cables was proposed.The results show that the joint support uses the full-length anchorage to increase the elastic modulus of bottom layer of the composite roof,reducing the deflection of bottom layer of the composite roof.Then,it uses the anchor cables to combine the various layers of the composite roof into a whole,forming a composite beam structure,thus the overall deflection of the composite roof is reduced.The field monitoring shows that the amount of convergence of the roof and floor plates decreases by 64%,the separation phenomenon is not found in the roof,and the maximum crack depth decreases from 8.1 m to 3.8 m,with the reduction of 53.80%.The stability of the coal roadway is significantly improved.The results can provide reference for controlling the collapse and instability of deep-buried composite roof strata separation.