To provide a reference for the evaluation of corrosion rate under dynamic metro stray current, both simulated experiments in laboratory and coupon tests in the field were conducted to explore the corrosion behavior and the relationship between corrosion rates and dynamic DC interference parameters of buried pipelines. The results show that the dynamic period has a significant influence on the corrosion rate and the ratio of actual corrosion rate to the theoretical corrosion rate. The statistical data of pipe to soil potentials or current densities of coupons electrically connected to pipelines obtained from the field in many cities of China show that the dynamic fluctuation periods under metro stray current are within the range of 0–300 s, among which the majority of fluctuation periods distribute from 50 to 200 s. The dynamic fluctuation of pipe to soil potentials and current densities of coupons exhibits symmetric or asymmetric characteristics. Under the situation of symmetric positive and negative current density, the ratio of the actual corrosion rate to the theoretical corrosion rate ranges from about 4% to 22% under the typical dynamic periods range from 50 to 200 s based on the simulated experiments results in the laboratory. Besides, two corrosion rate assessment methods, including the positive shifting and time ratios of off-potentials and symmetrical or asymmetric characteristics of DC current density of coupons were proposed. In addition, the evaluation of the on-potential criteria to assess the corrosion risk of time-variant anodic interference was also discussed in the paper.

中文翻译：

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动态地铁杂散电流下埋地管道腐蚀速率评估研究

为为地铁动态杂散电流下腐蚀速率的评价提供参考，通过室内模拟实验和现场挂片试验，探讨了埋地管道的腐蚀行为以及腐蚀速率与动态直流干扰参数之间的关系。结果表明，动态周期对腐蚀速率和实际腐蚀速率与理论腐蚀速率的比值有显着影响。从国内多个城市现场获得的管道电连接挂片的管土电位或电流密度统计数据表明，地铁杂散电流下的动态波动周期在0~300 s范围内，其中大多数的波动周期分布在 50 到 200 秒之间。管对土壤电位和试样电流密度的动态波动表现出对称或不对称的特性。在正负电流密度对称的情况下，根据模拟实验结果，在典型的50~200 s动态周期下，实际腐蚀速率与理论腐蚀速率的比值在4%~22%之间。实验室。此外，提出了两种腐蚀速率评估方法，包括断电势的正偏移和时间比以及试样直流电流密度的对称或不对称特性。此外，本文还讨论了评估时变阳极干扰腐蚀风险的通电标准的评估。