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海水中氯离子的侵蚀是影响钢筋混凝土结构在海洋环境中耐久性的一个重要的因素,而混凝土表面氯离子浓度是研究氯离子侵蚀的重要指标之一。由于混凝土结构沿海拔不同高度的服役环境不同,表面氯离子浓度随高程是变化的,但其分布存在一定的规律。根据浙江东部沿海地区某混凝土码头结构表面氯离子浓度的实测数据,通过数据统计分析,提出表面氯离子浓度随高度呈单峰高斯分布的规律;通过建立BP神经网络预测模型,验证其高斯分布规律假设的合理性。在对浙东沿海某混凝土码头及日本不同海域混凝土码头的表面氯离子浓度实测数据进行概率统计分析后,得到沿海混凝土结构的最严重氯离子侵蚀区域为海拔在0.4～1.6m,其海水浸润时间比为0.285～0.478,应重点加强该区域结构的抗氯侵蚀能力。最后,通过对实测数据的归一化处理,建立了基于高斯函数的海港码头混凝土表面氯离子浓度的高度影响系数和海水浸润时间比影响系数经验表达式。
The corrosion of chloride ion in seawater is one of the most important factors that affect the durability of reinforced concrete structure in marine environment. However, the chloride ion concentration on concrete surface is one of the important indexes for studying chloride ion erosion. Due to the different service environment of concrete structures at different altitudes, the surface chloride ion concentration varies with elevation, but there is a certain regularity in its distribution. According to the measured data of chloride ion concentration on the surface of a concrete wharf in the eastern coastal area of Zhejiang, the rule that the surface chloride ion concentration is single peak Gaussian distribution is proposed through the statistical analysis of the data. The BP neural network prediction model is established to verify the Gaussian distribution law Assumptions of rationality. After probabilistic statistical analysis of measured surface chloride ion concentrations at a concrete wharf in the coastal area of eastern Zhejiang and concrete wharves in different sea areas of Japan, the most serious area of chloride ion erosion in coastal concrete structures is 0.4-1.6 m above sea level with seawater infiltration time The ratio of 0.285 ~ 0.478, should focus on strengthening the region’s ability to resist chlorine erosion. Finally, through the normalization of the measured data, the empirical formula for the influence coefficient of the chloride ion concentration on the concrete surface of the harbor terminal based on the Gaussian function and the influence ratio of the seawater infiltration time ratio was established.