Abstract
The Kumamoto Port area has such very unique characteristics as the largest tidal level difference in Japan, very poor ground with soft clay deposited about 40m thick, and shallow and wide tidal flat. Therefore new technical developments are inevitably required to overcome these difficulties for economical and efficient port construction. This paper shows the summary of a new type of dike (breakwater) developed in this Port as one of such technical developments. This dike is designed to resist the external lateral force (waves) by short piles driven into the soft ground. As a result of long and energetic study, this type of dike which is suitable for use in a sea area with a soft bottom ground and relatively gentle waves, made no requirement of soil improvement 'possible. The construction cost of the dike is only about one-sixth that of the conventional gravity-type dike.
