Study on stray current corrosion of buried metal in layered soil

Abstract

In order to study the effect of layered soil structure on the stray current corrosion of buried metal in urban rail transit, a micro experimental platform for stray current corrosion is established. The research results are obtained by observing the corrosion morphology of buried metal, weighing the mass loss and calculating the corrosion rate. Firstly, the magnitude of stray current in layered soil structure is measured according to the FEM experimental model. Then, with a stray current as the experimental group and without a stray current as the control group studying the effects of the burial depth of metal, soil resistivity and layered soil structure on corrosion respectively. The experimental results show that the degree of stray current corrosion on buried metal in the layered soil structure will be slowed down comparing with the single-layer uniform soil structure, and the degree of stray current corrosion on buried metal will be decreased with the increasing of soil resistivity. Stray current corrosion is mainly concentrated in the anode region of buried metal, and the stray current corrosion of buried metal will be exacerbated with the stray current. In the same soil environment, the closer the buried metal is to the rail, the more serious the corrosion is. Finally, a multiphysics simulation model corresponding to the experiment is established using COMSOL simulation software. After comparison and verification, the simulation results are basically consistent with the experimental results, which prove the accuracy of the experimental results. A theoretical basis for the protection and design of stray current corrosion of buried metal can be provided by the research results.