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

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.