Study on corrosion behavior and mechanical performance degradation prediction of bolts in high mineralized corrosion environment

Deep coal mining faces high mineralized corrosion environment. To explore the corrosion characteristics of bolts in deep coal mining, the corrosion behavior and performance degradation law of ordinary bolts and new zinc-infiltrated bolts in high mineralized corrosion environment were studied by corrosion experimental, XRD and tensile test, the time-varying model for bolts performance degradation was established. The results show that: The corrosion morphologys of bolts in high mineralized corrosion environment are pitting corrosion. The ion erosion resistance of zinc-infiltrated bolts is significantly stronger than that of ordinary bolts. The increase of ion concentration will aggravate the performance degradation of bolts. The corrosion depth of bolts is linearly positively correlated with their strength loss. Based on the idea of number prediction and size homogenization of corrosion pits, the time-varying model for bolts performance degradation was derived by combining experimental data, pitting corrosion model and Weibull distribution. Based on the model analysis, it was found that the Cl− concentration and temperature are exponentially negatively correlated with the service life of bolts. Finally, the anti-corrosion support recommendations centered on the zinc-infiltration process were proposed.