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2014 Vol.30, Issue 7 Preview Page
Characteristics and Causes of Wave-Induced Settlement in Caisson Breakwater: Focusing on Settlement Data

파랑에 의한 방파제 케이슨 침하 경향 및 원인 분석: 침하 계측자료를 중심으로

Tae-Hyung Kim1*
,
Jung-Man Nam2
,
In-Sok Kim3
,
Seong-Kyu Yun4
김 태형1*
,
남 정만2
,
김 인석3
,
윤 성규4
1Prof., Dept. of Civil Engrg., Korea Maritime and Ocean Univ.
2Director. Songha Construction Co.
3Chief, Road Management Center, Jeju Special Self-Governing Province
4Graduate Student, Dept.. of Urban Management, Kyoto Univ.
1한국해양대학교 공과대학 건설공학과 교수
2송하건설 이사
3제주특별자치도 도로관리사업소 도로안전관리과장
4교토대학교 공학연구과 도시사회공학전공 박사과정
*교신저자. *Corresponding Author. 
31 July 2014. pp. 27-40
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Abstract

So far, studies on the settlement of breakwater have mainly been conducted through numerical model tests focusing on an analysis or through the laboratory wave tank tests using a scaled model. There has not been a study on the settlement that is measured in an actual breakwater structure. This study analyzed the data of settlement that has been measured in an actual caisson breakwater for a long time and the characteristics and causes of wave-induced settlement in the caisson (including beneath ground), based on qualitative aspect, were examined. The analysis revealed that wave clearly has an effect on the settlement in caisson, especially in the condition of high wave such as typhoon. Caisson settlement is caused by the liquefaction of ground, which is due to the increase of excess pore pressure, the combination of oscillatory excess pore pressure and residual excess pore water pressure, and the solidification process of ground due to dissipation of the accumulated excess pore pressure. The behavior of excess pore pressure in the ground beneath the caisson is entirely governed by the behavior of the caisson. Ground that has gone through solidification is not likely to go through liquefaction in a similar or a smaller wave condition and consequently, the possibility of settlement is reduced.

Keywords
Oscillatory pore water pressure
Residual pore water pressure
Liquefaction
Progressive solidification,
Wave-induced settlement
Caisson Breakwater

지금까지의 방파제 침하와 관련된 연구는 주로 해석위주의 수치모형실험 또는 축소모형을 이용한 실내수조모형실험을 통해 이루어졌다. 현재까지 실제 방파제 구조물에서 계측된 침하를 이용한 연구는 이루어지 않았다. 본 연구에서는 실제 케이슨 방파제에서 장기간 계측된 침하 자료를 분석해 정성적인 측면에서 파동에 의한 케이슨의(하부지반 포함)침하 경향과 그 원인을 분석하였다. 분석 결과, 케이슨 침하에 파랑의 영향이 있음을 분명하게 확인할 수 있었다. 특히 태풍과 같은 고파랑 조건에서는 그 경향이 뚜렷하게 나타났다. 케이슨 침하는 파랑에 의한 해저지반에서의 진동과잉간극수압과 잔류과잉간극수압의 합으로 표현되는 과잉간극수압의 증가에 의한 지반의 액상화와 축적된 과잉간극수압의 소산에 따른 지반의 고밀도화 과정을 통해 발생된다. 케이슨 하부 지반의 과잉간극수압 거동은 전적으로 케이슨 거동에 지배된다. 고밀화과정을 경험한 지반은 동급의 또는 그 보다 작은 파랑 조건에서는 액상화 발생 가능성이 현저하게 줄어들어 결과적으로 침하 발생도 감소된다.

References
1
1.Biot, M.A. (1941), “General theory of Three-dimensional Consolidation”, Journal of Applied Physics, Vol.12, pp.155-165.
2
2.Budhu, M. (2010), Soil Mechanics and Foundations - 3rd edition, John Wiley & Sons, Inc.
3
3.Cho, S.-H. (2007), A Study on the Characteristics of Cheju Island’s Beach Sands, Cheju National University, Master Thesis.
4
4.Hsu, J.R.C. and Jeng, D.S. (1994), “Wave-induced Soil Response in an Unsaturated Anisotropic Seabed of Finite Thickness”, Intl. J. for Numerical Analytical Methods in Geomechanics, 18(11), 785-807.
5
5.Kang, G.-C., Yun, S.-K., Kim, T.-H., and Kim, D. (2013), “Numerical Analysis on Settlement Behavior of Seabed Sand-Coastal Structure Subjected to Wave Loads”, Journal of Korean Society of Coastal and Ocean Engineers, Vol.25, No.1, pp.20-27. (In Korean)
6
6.Kianoto, T. and Mase, H. (1999), “Boundary-layer Theory for Anisotropic Seabed Response to Sea Waves”, Journal of Waterway, Port, Coastal and Ocean Eng., ASCE, Vol.125, No.4, pp.187-194.
7
7.Kim, T.-H., Nam, J.-M., Ge, L., and Lee, K.-I. (2008), “Settlement Characteristic of Beach Sands and Its Evaluation”, Marine Georesources & Geotechnology, Vol.26, No.2, pp.67-85.
8
8.Kirca, V. S. Ozgur, Sumer, B. Mutlu, and Fredsøe Jørgen (2013), Residual Liquefaction of Seabed under Standing Waves, Journal of Waterway, Port, Coastal, and Ocean Engineering, Vol.139, No.6, pp.489-501.
9
9.Kudella, M. and Oumeraci, H. (2004a), Wave-induced Pore Pressure in the Sandy Seabed underneath a Caisson Breakwater-Experimental Results of Large-Scale Model Tests, Technical Rep., Technical Univ. of Braunschweig, Leichtweiss-Institute.
10
10.Kudella, M. and Oumeraci, H. (2004b), “Wave-induced Transient and Residual Pore Pressure in the Sand Bed underneath a Caisson Breakwater-Processes Leading to Liquefaction”, Proc., Int. Conf. on Cyclic Behaviour of Soils and Liquefaction Phenomena, Bochum, Germany, Balkema, Rotterdam, pp.411-424.
11
11.Kudella, M., Oumeraci, H., de Groot, M.B., and Meijers, P. (2006), “Large-Scale Experiments on Pore Pressure Generation underneath a Caisson Breakwater”, Journal of Waterway, Port, Coastal, and Ocean Engineering, Vol.132, No.4, pp.310-324.
12
12.Lee, K.-H., Baek, D.-J., Kim, D.-S., Kim, T.-H., and Bae, K.-S. (2014), Numerical Simulation on Seabed-Structure Dynamic Responses due to the Interaction between Waves, Seabed and Coastal Structure, Journal of Korean Society of Coastal and Ocean Engineers, Vol.26, No.1, pp.49-64. (In Korean)
13
13.Li, J. and Jeng, D.S. (2008), “Response of a Porous Seabed Around Breakwater Heads”, Ocean Eng., Vol.35, pp.864-886.
14
14.Madsen, O.S. (1978), “Wave-induced Pore Pressure and Effective Stresses in a Porous Bed”, Geotechnique, Vol.28, pp.377-393.
15
15.Mase, H., Sakai, T., and Sakamoto, M. (1994), “Wave-induced Porewater Pressures and Effective Stresses around Breakwater”, Ocean Eng., Vol.21, No.4, pp.361-379.
16
16.Mei, C.C. and Foda, M.A. (1981), Wave-induced Response in a Fluid-filled Poroelastic Solid with a Free Surface - A Boundary Layer Theory”, Geophysical Journal of the Royal Astrological Society, Vol.66, pp.597-631.
17
17.Miyamoto, J., Sassa, S., and Sekiguchi, H. (2004), “Progressive Solidification of a Liquefied Sand Layer during Continued Wave Loading”, Geotechnique, Vol.54, No.10, pp.617-629.
18
18.Okusa, S. (1985), “Wave-induced Stresses in Unsaturated Submarine Sediments”, Geotechnique, Vol.32, No.3, pp.235-247.
19
19.Sassa, S. and Sekiguchi, H. (1999), “Analysis of Wave-induced Liquefaction of Beds of Sand in Centrifuge”, Geotechnique, Vol.49, No.5, pp.621-638.
20
20.Sassa, S. and Sekiguchi, H. (2001), “Analysis of Wave-induced Liquefaction of Sand Beds”, Geotechnique, Vol.51, No.12, pp.115-126.
21
21.Sassa, S., Sekiguchi, H., and Miyamoto, J. (2001), “Analysis of Progressive Liquefaction as a Moving-boundary Problem”, Geotechnique, Vol.51, No.10, 847-857.
22
22.Seed, H.B. and Rahman, M.S. (1978), “Wave-induced Pore Pressure in Relation to Ocean Floor Stability of Cohesionless Soil”, Marine Geotechnology, Vol.3, No.2, pp.123-150.
23
23.Sekiguchi, H., Kita, K., and Okamoto, O. (1995), “Response of Pore-elastoplastic Beds to Standing Waves”, Soils and Foundations, Vol.35, No.3, pp.31-42.
24
24.Sumer, B.M. and Fredsøe, J. (2002), The Mechanics of Scour in the Marine Environment, World Scientific, 536pp.
25
25.Sumer, B.M., Hatipoglu, F., and Fredsøe, J. (2004), “The Cycle of Soil Behaviour during Wave Liquefaction”, Book of Abstracts, Paper 171, 29th International Conference on Coastal Engineering, 19-4.September, 2004, National Civil Engineering Laboratory (LNEC), Lisbon, Portugal,
26
26.Sumer, B.M., Hatipoglu, F., Fredsøe, J., and Sumer, S.K. (2006), “The Sequence of Sediment Behaviour during Wave-induced Liquefaction”, Sedimentology, Vol.53, pp.611-629.
27
27.Ulker, M.B.C., Rahman, M.S., and Guddati, M.N. (2010), “Wave- induced Dynamic Response and Instability of Seabed around Caisson Breakwater”, Ocean Eng., Vol.37, pp.1522-1545.
28
28.Yamamoto, T., Koning, H., Sllmejjer, H., and Van Hijum, E. (1978), “On the Response of a Poroelastic Bed to Water Waves”, Journal of Fluid Mechanics, Vol.87, pp.193-206.
29
29.Ye, J., Jeng, D., Liu, P.L.-F., Chan, A.H.C, Ren, W., and Changqi, Z. (2014), “Breaking Wave-induced Response of Composite Breakwater and Liquefaction in Seabed Foundation”, Coastal Eng., Vol.85, pp.72-86.
30
30.Yuhi, M. and Ishida, H. (2002), “Simplified Solution of Wave- induced Seabed Response in Anisotropic Seabed”, Journal of Waterway, Port, Coastal and Ocean Eng., ASCE, Vol.128, No.1, pp.46-50.
31
31.Zen, K. and Yamazaki, H. (1990a), “Mechanism of Wave-induced Liquefaction and Densification in Seabed”, Soils and Foundations, Vol.304, pp.90-104.
32
32.Zen, K. and Yamazaki, H. (1990b), “Oscillatory Pore Pressure and Liquefaction in Seabed Induced by Ocean Waves”, Soils and Foundations, Vol.304, pp.147-161.
Information
  • Publisher :The Korean Geotechnical Society
  • Publisher(Ko) :한국지반공학회
  • Journal Title :Journal of the Korean Geotechnical Society
  • Journal Title(Ko) :한국지반공학회 논문집
  • Volume : 30
  • No :7
  • Pages :27-40
  • Received Date : 2014-04-06
  • Revised Date : 2014-05-28
  • Accepted Date : 2014-07-02
  • DOI :https://doi.org/10.7843/kgs.2014.30.7.27
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