著者

河田 恵昭

出版者

日本自然災害学会

雑誌

自然災害科学 (ISSN:02866021)

巻号頁・発行日

vol.7, no.2, pp.21-35, 1988-06-30

---

It is found that in Japan composite breakwaters have been exclusively constructed, while in other countries rubble mound breakwaters are very popular. This discrepancy is quite clear. The principles of breakwaters were established in Europe around 1850. At that time, wave motion in water was of course still incompletely understood. The established principles are as follows; a vertical wall reflects waves and a sloping wall absorbs wave energy through its breaking. The Yatoi who were hired foreigners had introduced the technology of breakwater construction in early modern Japan. It is pointed out that composite breakwaters have been widely used in our country since about 1900 and because it has been improved the vertical wall can control both wave forces due to breaking and reflection.