Research on Parameter Fluctuation Characteristics and Effects on Corrosion Rates under Dynamic DC Stray Current from Metro System

摘要

With the large-scale construction of metro systems in many cities of China, a growing number of buried metal pipelines are experiencing dynamic DC stray current in recent years. However, less work has been carried out on the effect of dynamic DC stray current on corrosion rate of steel structures. Therefore, there is a lack of consistent corrosion evaluation criterion under dynamic DC stray current in the world currently. Based on measured dynamic fluctuating parameters on buried pipelines interfered by dynamic DC stray current from metro system, the fluctuation characteristics, such as fluctuating period and amplitude were analyzed systemically. Corrosion coupons were buried near the pipelines interfered by dynamic DC stray current and connected electrically with the pipeline, and after 6 or 12 months, the corrosion coupons were dug out and corrosion rates of them were obtained by weight loss tests. The relationships between dynamic fluctuation parameters and corrosion rates were analyzed, which could provide reference for the buildup of corrosion evaluation criterion under dynamic DC stray current.