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

파랑작용에 의한 준설토 지반의 안정성에 관한 실험적 연구

  • Kang, Yoon-Koo (Port Management Team, Civil Works Division, Engineering & Construction Group, Samsung Cporporation)
  • 강윤구 (삼성물산 건설부문 토목사업본부 항만팀)
  • Published : 2006.08.01

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.

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References

  1. 한국수자원공사. '시화호 갈대습지공원V', http://www.kowaco. or.kr/
  2. Kang, Y.K., Takahashi, S., Okudaira, A. and Kuroda, T. (2001). 'Field Survey on Natural and Artificial Tidal Flats -Stability of Foreshore Tidal Flats against Wave Actions-, Technical Note of the Port and Harbour Res. Inst., Ministry of Land, Infrastructure and Transport, Japan, No 1011, 78p(in Japanese)
  3. Matui, T, Ohara, H. and Ito, T. (1980). 'Cyclic stress-strain history and shear characteristics of clay', J. Geotechnical Engineering Division, ASCE, Vol 106, No 3, pp 1101-1120
  4. Tsuchida, T. and Gomyo, M. (1999). 'On the Stability of seabed under the Cyclic Pressure Change due to Waves', Annual J. of Castal Engineering, JSCE, Vol 46, pp 596-600(in Japanese)
  5. WAVE (2001). 'Introduction, Guideline for the conservation and creation of ecosystems in relation to coastal development', Vol 1, Waterfront Vitalization and Environment Research Center, Tokyo, Japan, 117p
  6. Yamazaki, H., Zen, K., Kagaya, H. and Tachishita, T. (1991). 'Strength and deformation characteristics of clays due to cyclic loading', Rep. of the Port and Harbour Res. Inst., Ministry of Land, Infrastructure and Transport, Japan, Vol 30, No 4, pp 65-83(in Japanese)
  7. Zen, K. and Yamazaki, H. (1990a). 'Mechanism of wave-induced liquefaction and densification in seabed', Soils and Foundations, Vol 30, No 4, pp 90-104 https://doi.org/10.3208/sandf1972.30.4_90
  8. Zen, K. and Yamazaki, H. (1990b). 'Oscillatory pore pressure and liquefaction in seabed induced by ocean waves', Soils and Foundations, Vol 30, No 4, pp 147-161 https://doi.org/10.3208/sandf1972.30.4_147