Study on the corrosion damage behavior and anti-corrosion methods of mining anchor cables in high-mineralized water environments

Corrosion failure of anchor cables caused by highly mineralized water in deep coal mine roadways has become increasingly severe, often leading to local roof block falls or even large-scale rock collapses, thereby threatening safe mining operations. To address this issue, laboratory salt-spray accelerated corrosion tests were conducted on anchor cables. Corrosion damage behavior under a 5% chloride ion concentration was systematically investigated using metallographic analysis, scanning electron microscopy (SEM), and energy-dispersive spectroscopy (EDS), and the associated damage mechanisms were elucidated. Results show that in a high-mineralized water environment, Cl⁻ readily induces uniform corrosion and pitting corrosion of anchor cables. At early corrosion stages, a yellow-brown rust layer forms on the cable surface and gradually develops into a loose, porous structure as exposure time increases, while corrosion rate exhibits a nonlinear trend, decreasing first and then increasing. As Cl⁻ penetrates into the matrix, Fe atoms around inclusions preferentially dissolve due to lattice energy differences, promoting pit initiation. Metallographic and SEM-EDS analyses indicate that corrosion products mainly consist of oxides and sulfide-type inclusions, and corrosion progression causes grain boundary degradation, pore formation, and preferential corrosion occurs at the inclusion-matrix interface, which significantly weaken anchor cable strength and ductility. Through comparative analysis of corrosion morphology and post-corrosion physical and mechanical properties of anchor cables with different coatings, aluminum-zinc coating is identified as an effective anti-corrosion process. In addition, effects of post-corrosion cable morphology on anchorage load-bearing capacity, and further clarifies the degradation laws of anchor cables under single-factor and coupled effects, as well as their engineering applicability are examined. These findings provide a theoretical basis and technical support for corrosion protection of anchor cables in coal mines. • Elucidated corrosion mechanisms and microstructural characteristics of anchor cables in severe corrosive conditions. • Evaluated and optimized four anti-corrosion processes and their corresponding control methods. • Revealed nonlinear characteristics of anchor-cable corrosion rate and clarified influence of elemental distributions. • Summarized effects of stress, corrosion, and their stress–corrosion coupling on anchor-cable corrosion.