Abstract
Recently, traffic hindrances due to wave overtopping frequently occur at coastal railways close to the seawall. In this paper, track bed damages of a coastal railway facing to the sea of Japan were investigated, and the countermeasures were proposed based on the results of hydraulic experiments. The characteristics of wave pressure distribution behind the seawall were examined by wave overtopping experiments using random waves under the scale of 1/40. It was shown that wave overtopping occurs when the offshore wave height becomes higher than 4.0m. Based on the time series of wave pressure obtained by wave overtopping experiments, wave action was also reproduced by water falling experiments in the scale of 1/4. The track bed facilities, such as ballast, rail and wood crossties, were modeled in the experimental channel. The ballast scouring due to wave overtopping was reproduced by the falling water related to the offshore wave height. The relationship between the ballast damage ratio and the offshore wave height was disclosed for the typical storm wave conditions. As for the countermeasures against the ballast damage, the effect of installing a net on the track bed and construction of the upright wall was revealed based on the experimental results.
