为解决沉管隧道钢结构表面阴极保护电位难以计算和测试的问题,采用数值模拟技术,对某项目阴极保护设计方案进行了优化,并使用缩比模型间接验证了模拟结果的准确性。结果表明:对于沉管隧道来说,由于无法在沉管钢壳底部布置牺牲阳极,欠保护区域通常出现在沉管底部;若将阳极均匀布置在除钢壳底面外的其他表面,沉管钢壳的顶面或侧面与底面之间的电位差为70~100 mV,钢壳底面处于欠保护状态;在沉管钢壳的侧面增加牺牲阳极的数量,沉管底面电位的负移量较大,牺牲阳极的保护效果较好。

In order to solve the problem that the cathodic protection potential on the surface of immersed tunnel steel structure was difficult to calculate and test, the cathodic protection design of a project was optimized by numerical simulation technology. The accuracy of the simulation results was indirectly verified by the scale model. The results showed that for the immersed tunnel, the under-protected area usually appears at the bottom of the immersed tube because the sacrificial anode cannot be arranged at the bottom of the immersed tube steel shell. If the anode was evenly arranged on other surfaces except the bottom surface of the steel shell, the potential difference between the top or side of immersed tube steel shell and the bottom surface was 70-100 mV, and the bottom surface of steel shell was in an under-protected state. By increasing the number of sacrificial anodes on the side of immersed tube steel shell, the negative shift of the potential at the bottom of immersed tube was larger, and the protection effect of sacrificial anode was better.