Abstract: Corrosion of the steel arch in the primary support in subsea tunnel reduces the primary support′s flexural capacity. Electrically accelerated corrosion tests obtain steel arches with different corrosion rates. Concrete beams of steel arches with different corrosion rates are tested to reflect the influence of corrosion on the flexural capacity of steel arches from a macroscopic point of view. The numerical simulation analysis results show the following: (1) The flexural capacity of corroded Isteel concrete beams decreases with increased corrosion rate. The average flexural capacity decreases by 5.1 kN as the corrosion rate increases by 1%. (2) Transverse cracks appear during the loading process of the corroded Ishaped steelconcrete beam when the corrosion rate is less than or equal to 1.5%, and longitudinal penetrated cracks appear when the corrosion rate is greater than 1.5%. (3) As the corrosion rate increases, the bonding effect between concrete and Ishaped steel weakens, and concrete stress and strain increase. On the contrary, the stress and strain of Ishaped steel decrease.

Key words: subsea tunnel, steel arch corrosion, flexural capacity, flexural capacity test, numerical simulation