Surface roughness characteristics and stochastic model of corroded steel foundation in submarine soil environment

With the rapid development of ocean engineering, many types of steel foundation have been developed to support above ground structures, which encounter great corrosion risk and serious safety hazards in whole service life. Though lots of studies have been devoted to corrosion loss of sectional area and deterioration of strength, little effect focuses on the surface roughness characteristics of corroded steel foundation in submarine soil, which have significant impact on the soil-structure interaction and even on the bearing capacity of overall structure. Electrolytic accelerated corrosion experiments are conducted to investigate the surface roughness characteristics of corroded steel in marine clay soil. The experiment results show that the roughness parameters, i.e. the arithmetic mean height, the maximum height and the standard deviation, have a S-shape growth with the degree of corrosion represented by mean corrosion depth. Moreover, the probability distribution of corrosion height on each corroded surface is statistically analyzed, which generally follows Gauss distribution. Based on the experimental results and roughness parameter change law, a stochastic model is constructed to reconstruct the surface topography of corroded steel with considering different degrees of corrosion, which is verified by comparing the predicated results with experiment data. The findings of surface roughness characteristics and developed stochastic model are helpful for studying the soil-steel foundation interaction characteristics and bearing capacity of ocean engineering structure with considering the corrosion effect.