矿用锚索捻距与拉伸力学性能及锚固效果关系研究

Study on the relationship between lay distance and tensile mechanical properties and anchorage effect of mine anchor cable

矿用锚索主要由多根钢绞线缠绕而成,具有可弯曲、抗破断能力强及成本低廉等优点,在煤矿巷道围岩,特别是巷道顶板稳定性控制中广泛采用。捻距是制作锚索的重要参数之一,当选取煤矿锚索时,因了解尚浅而往往忽略这一参数。为探究捻距参数对锚索拉伸力学性能与锚固效果是否存在影响,论文采用理论分析与室内试验相结合的方法,初步厘清了捻距参数对锚索拉伸时的几何变形特征的影响,明晰了其对锚索锚固力的影响机制。基于试验获得的锚索拉伸及锚固拉拔数据构建数值模拟模型,与井下试验结果进行对比,得到了捻距与其极限拉伸载荷、最大锚固力的关系式,获取了能够充分发挥锚索拉伸力学性能与锚固效果的最佳捻距。研究结果表明:当锚索受到拉伸时,在一定范围内捻距与延伸率的关系为负相关,与拉伸极限载荷的关系为正相关;锚索-锚固剂界面存在一定的几何匹配关系,当捻距减小至其13倍公称直径时,最大锚固力随着捻距的减小而增大;综合分析锚索极限拉伸载荷与最大锚固力等因素发现,能够充分发挥锚索拉伸力学性能与锚固效果的最佳捻距为13~14倍公称直径。研究成果增加了锚索捻距对拉伸力学性能影响的认识,明晰了对其锚固机制的理解,为锚索制作及选取煤矿锚索提供了参考及理论支撑。

The mine anchor cable,which is mainly made of multiple steel strands,has the advantages of bendability,strong breaking resistance,and low cost.It is widely used in the stability control of coal roadway surrounding rock,especially the roadway roof.The twist is one of the important parameters for making anchor cable,which is often ignored in coal mines because of the lack of understanding when selecting anchor cable.In order to explore whether the lay distance parameter has an influence on the tensile mechanical properties and anchoring effect of anchor cable,this paper combines theoretical analysis with laboratory tests to preliminarily clarify the influence of the lay distance parameter on the geometric deformation characteristics of anchor cable during tensile and clarify its influence mechanism on the anchorage force of anchor cable.Based on the experimental data of anchor cable tension and anchorage drawing,a numerical simulation model was constructed,compared with underground test results,and the relationship between the twist distance and the ultimate load and the maximum anchorage force was obtained,and the optimal twist distance which could give full play to the tensile mechanical properties and anchorage effect of cable was obtained.The results show that when the anchor cable is stretched,the twist distance has a negative correlation with elongation and a positive correlation with tensile limit load in a certain range.There is a certain geometric matching relationship between cable and anchorage agent interface.When the twist is reduced to 13 times its nominal diameter,the maximum anchorage force increases with the decrease of the twist.Considering the ultimate tensile load and maximum anchorage force of anchor cable,it is found that the best twist range which can give full play to the tensile mechanical properties and anchorage effect of anchor cable is 13-14 times the nominal diameter.The research results increase the understanding of the influence of anchor cable twist on its tensile mechanical properties,clarify the understanding of its anchorage mechanism,and provide a reference and theoretical support for the production of anchor cables and the selection of anchor cables in coal mines.