Modelling Cathodic Protection Performance of Steel Pipeline under Dynamic Soil Moisture Environment

Abstract Cathodic protection (CP) is the principal engineering method for mitigating external corrosion of buried steel pipelines, playing a critical role in ensuring pipeline structural safety and service reliability. CP performance is influenced by the properties of surrounding soil, such as moisture content. Soil moisture is highly dynamic and responds sensitively to environmental drivers such as rainfall and evaporation, and this variability directly affects the effectiveness of CP. This study aims to develop an integrated finite element modeling framework that couples unsaturated soil moisture dynamics with moisture-dependent electrochemical polarization behavior to quantitatively evaluate CP performance under realistic, climate-driven moisture fluctuations. The model results show fluctuations of pipe-soil potential applied by the impressed current CP under dynamic soil environment. By linking hydrological variability of soil with electrochemical behavior of steel, the proposed method can be used for more reliable CP design and adaptive management under changing soil environments.