ANALYSIS ON TRAFFIC DISTURBANCE OF RAILWAY LOCATED BEHIND PARAPET DAMAGED SEAWALL DUE TO HIGH WAVES

Abstract

 A train of H line facing the Pacific Ocean was stopped by a driftwood which had run up on the railway track due to high waves between the T and K stations on September 5, 2006. It is estimated that the driftwood was run up by overtopping waves through the opening area of damaged seawall due to wave action with a swell condition. This study clarified the wave pressure characteristic acting on a seawall parapet by random waves with an experiment at a scale of 1/30 that reproduced sea wave and tidal conditions when the traffic disturbance happened. The wave overtopping rate, as well as run up rate of driftwood for different lengths and specific gravity, were measured for the damaged parapet portion of the seawall. In addition, the driftwood run-up pattern on the railway track was analyzed due to flow velocity of wave overtopping by a dam-break wave in a large experiment of a scale of 1/10. As a result, it was shown that the specific gravity of the driftwood which caused traffic disturbance on site was about 0.7.