Study on Chloride Ion Erosion Model and Law of Concrete Considering Stress

During the operation of the tunnel, chloride ion erosion is one of the main reasons leading to the cracking of the tunnel concrete lining and the decrease of the structural strength. Chloride ion penetrates into the surface of the steel bar, which will cause the corrosion and depassivation of the steel bar, and eventually lead to the cracking and spalling of the concrete protective layer and the significant decrease of the structural bearing capacity. These problems seriously affect the long-term stability and durability of the tunnel. In order to improve the durability of the lining structure and prolong the service life of the structure, it is very important to explore the erosion and diffusion mechanism of chloride ions in concrete under different stress levels. In this paper, the diffusion mechanism of chloride ions in concrete members is deduced according to Fick 's first law and Fick 's second law. The chloride ion erosion analysis model considering the influence of stress level of members is established by infinitesimal method. The stress level is introduced as a key variable to reveal the law of chloride ion erosion in members under different stress levels. The model proposed in this paper provides a new perspective for further study of chloride ion erosion behavior of tunnel lining under the influence of stress, and provides a scientific basis for engineering design and maintenance.