Experimental Study on the Stability of Dredged Soil Bed under Cyclic Wave Actions

J. Ocean Eng. Technol. 2006;20(4):43-49.

Kang, Yoon-Koo;

Port Management Team, Civil Works Division, Engineering & Construction Group, Samsung Cporporation;

파랑작용에 의한 준설토 지반의 안정성에 관한 실험적 연구

강윤구;

삼성물산 건설부문 토목사업본부 항만팀;

Keywords: Dredged mud, Cyclic wave actions, Liquefaction, Hydraulic model test, Stability against wave action, Artificial tidal flat

핵심용어: 준설점토, 파랑의 반복작용, 액상화, 수리모형실험, 내파안정성, 인공갯벌

Abstract

Detailed investigations were carried out on the stability of the dredged soil bed against wave actions, aimedat establishing the design method of artificial tidal flats using dredged soil. The soil was dredged at Nagoya port, Japan, and has a mean grain size of 0.013mm. Basic features of artificial dredged soil bed against wave actions were explained from a series of model experiments in a wave flume. The two types of section shapes were employed; one is a horizontal bed and the other is a sloped one. Changes of the bed profile, shear strength, grain size distribution and water content, according to the wave actions, were measured in detail. The cumulative effect of the wave actions, over about one week, was investigated. A dredged soil bed moves withthe wave actions with relatively small wave height. It should be especially. noted that the clay component is dissolved and flown out, away from the surface layer, and consequently the surface layer hardens, as if it is covered with sand. Wren the wave height is gradually increased, the bed is not liquefied and the shear strength of the dredged bed is increased by a wave-induced dissipation of pore pressures in the bed and a decrease of clay component by the wave-induced leakage.