抄録
Cathodic protection is applied to the steel quay constructed by driving a steel sheet into ocean bottom mud. In this case, the electric field formed by the steel sheet and sacrificial anode in seawater and ocean bottom mud is exactly governed by a nonlinear equation because of the ununiform specific resistant of the electrolyte. In order to simplify the calculation, the whole elctrolyte domain is divided into two uniform subregions by the water-mud interface. Moreover, the discretization of the water-mud interface is avoided by employing the Green's function available for a piecewise uniform electrolyte domain in the boundary integral equation. In this report, this method is applied to the cathodic protection problem of a steel quay, and the sacrificial anode position is investigated. Based on the calculated results, the following concluding points may be in order; (1) In the calculating model of the electric field formed by a cathodic protection system in seawater and ocean bottom mud, the variation of the specific resistant with depth in seawater or in ocean bottom mud can be ignored. Therefore, the electrolyte domain can be simply divided into two uniform subregions by the water-mud interface. (2) A reasonable position of the sacrificial anode should make the potential distribution on the cathodic surface more uniform, and results in a longer life-span of the sacrificial anode.
