Journal of Korean Society of Coastal and Ocean Engineers (한국해안·해양공학회논문집)

Korean Society of Coastal and Ocean Engineers (한국해안·해양공학회)
권호 표지
DOI QR코드

DOI QR Code

Numerical Simulation of Dynamic Response of Seabed and Structure due to the Interaction among Seabed, Composite Breakwater and Irregular Waves (I)

불규칙파-해저지반-혼성방파제의 상호작용에 의한 지반과 구조물의 동적응답에 관한 수치시뮬레이션 (I)

  • Lee, Kwang-Ho (Dept. of Energy Resources and Plant Eng., Kwandong Univ.) ;
  • Baek, Dong-Jin (Dept. of Civil Eng., Korea Maritime and Ocean Univ.) ;
  • Kim, Do-Sam (Dept. of Civil Eng., Korea Maritime and Ocean Univ.) ;
  • Kim, Tae-Hyung (Dept. of Civil Eng., Korea Maritime and Ocean Univ.) ;
  • Bae, Ki-Seong (Dept. of Ocean Civil Eng., Gyeongsang Univ.)
  • 이광호 (관동대학교 에너지자원플랜트공학과) ;
  • 백동진 (한국해양대학교 대학원 토목환경공학과) ;
  • 김도삼 (한국해양대학교 건설공학과) ;
  • 김태형 (한국해양대학교 건설공학과) ;
  • 배기성 (경상대학교 해양토목공학과)
  • Received : 2014.04.14
  • Accepted : 2014.06.27
  • Published : 2014.06.30
Download PDF
⟨ Previous Next ⟩

Abstract

Seabed beneath and near coastal structures may undergo large excess pore water pressure composed of oscillatory and residual components in the case of long durations of high wave loading. This excess pore water pressure may reduce effective stress and, consequently, the seabed may liquefy. If liquefaction occurs in the seabed, the structure may sink, overturn, and eventually increase the failure potential. In this study, to evaluate the liquefaction potential on the seabed, numerical analysis was conducted using the expanded 2-dimensional numerical wave tank to account for an irregular wave field. In the condition of an irregular wave field, the dynamic wave pressure and water flow velocity acting on the seabed and the surface boundary of the composite breakwater structure were estimated. Simulation results were used as input data in a finite element computer program for elastoplastic seabed response. Simulations evaluated the time and spatial variations in excess pore water pressure, effective stress, and liquefaction potential in the seabed. Additionally, the deformation of the seabed and the displacement of the structure as a function of time were quantitatively evaluated. From the results of the analysis, the liquefaction potential at the seabed in front and rear of the composite breakwater was identified. Since the liquefied seabed particles have no resistance to force, scour potential could increase on the seabed. In addition, the strength decrease of the seabed due to the liquefaction can increase the structural motion and significantly influence the stability of the composite breakwater. Due to limitations of allowable paper length, the studied results were divided into two portions; (I) focusing on the dynamic response of structure, acceleration, deformation of seabed, and (II) focusing on the time variation in excess pore water pressure, liquefaction, effective stress path in the seabed. This paper corresponds to (I).

해양 및 해안구조물 하부의 해저지반에 장시간 지속적인 고파랑이 작용하는 경우 진동성분과 잔류성분으로 구성되는 과잉간극수압의 증가에 따른 유효응력의 감소로 인하여 해저지반내에 액상화의 가능성이 나타나고, 일단 액상화가 발생되면 그의 진행에 따라 구조물의 침하 혹은 전도에 의해 종국적으로 구조물이 파괴될 가능성이 높아지게 된다. 본 연구에서는 2차원수치파동수로를 혼상류해석과 불규칙파동장으로 확장한 수치해석법을 적용하여 불규칙파동장하에서 해저지반상 및 혼성방파제의 표면상에서 시간변동의 동파압과 유속에 의한 전단응력을 산정하고, 그 결과를 지반의 동적거동을 정밀하게 재현할 수 있는 유한요소법에 기초한 탄소성해저지반응답용의 수치해석프로그램에 입력치로 적용하여 불규칙파동장에서 해저지반내에서 과잉간극수압 및 유효응력의 시공간적인 변화, 이로 인한 액상화, 그리고 지반의 시간변형과 케이슨의 시간변위 및 변위가속도 등을 정량적으로 평가한다. 이로부터 혼성방파제 전면 및 후면 하부의 해저지반내에서 액상화 가능성을 확인할 수 있었고, 이에 따라 액상화된 토립자는 흐름에 대한 저항력을 상실하므로 액상화된 지반은 세굴가능성이 클 것으로 판단된다. 또한, 액상화된 지반은 강도의 현저한 저하로 구조물의 진동변위가 증폭되고, 더불어 혼성방파제의 안정성에 큰 영향을 미칠 것으로 예상된다. 여기서, 본 연구의 전체 내용을 지면관계상 두 부분으로 나누며, 전반부를 (I)로 하여 구조물의 동적변위와 변위가속도 및 지반변형을 중심으로 다루고, 후반부를 (II)로 하여 지반내에서 간극수압의 시간변동, 액상화 및 유효응력경로 등을 상세히 다루며, 본 연구는 전반부인 (I)에 해당한다.

Keywords

References

  1. Biot, M.A. (1941). General theory of three-dimensional consolidation, J. of Applied Physics, 12, 155-165. https://doi.org/10.1063/1.1712886
  2. Burcharth, H.F.(1987). The lessons from recent breakwater failures. Developments in breakwater design, Invited Speech Presented at World Federation of Engineering Organizations Technical Congress, Vancouver.
  3. CDIT(2001). Research and development of numerical wave channel( CADMAS-SURF), CDIT library, 12 (in Japaneses).
  4. Chang, S.C., Chien, L.K., Lin, J.G. and Chiu, Y.F. (2007). An experimental study on progressive wave-induced stresses duration in seabed soil, J. of Marine Science and Technology, 15(2), 129-140.
  5. Chen, Y., Lai, X., Ye, Y., Huang, B. and Ji, M. (2005). Waterinduced pore water pressure in marine cohesive soils, Acta Oceanologica Sinica, 24(4), 138-145.
  6. Cheng, L., Sumer, B.M. and Fredsoe, J. (2001). Solutions l of pore pressure build up due to progressive waves, Intl. J. for Numerical and Analytical Methods in Geomechanics, 25, 885-907. https://doi.org/10.1002/nag.159
  7. Hirt, C.W. and Nichols, B.D. (1981). Volume of fluid(VOF) method for the dynamics of free boundaries, J. of Computational Physics, 39, 201-225. https://doi.org/10.1016/0021-9991(81)90145-5
  8. Iai, S., Matsunaga, Y. and Kameoka, T. (1992a). Strain space plasticity model for cyclic mobility, Soils and Foundations, Japanese Society of Soil Mechanics and Foundation Eng., 32(2), 1-15 (in Japanese).
  9. Iai, S., Matsunaga, Y. and Kameoka, T. (1992b). Analysis of undrained cyclic behavior of sand under anisotropic consolidation, Soils and Foundation, Japanese Society of Soil Mechanics and Foundation Eng., 32(2), 16-20 (in Japanese).
  10. Jeng, D.S. (1997). Wave-induced seabed response in front of a breakwater, PhD thesis, Univ. of Western Australia.
  11. Jeng, D.S. and Hsu, J.R.C. (1996). Wave-induced soil response in a nearly saturated seabed of finite thickness, Geotechnique, 46(3), 427-440. https://doi.org/10.1680/geot.1996.46.3.427
  12. Jeng, D.S. and Seymour, B.R. (2007). Simplified analytical approximation for pore-water pressure build up in marine sediments, J. of Waterway, Port, Coastal, and Ocean Eng., ASCE, 309-312.
  13. Jeng, D.S, Seymour, B. and Li, J. (2006). A new approximation for pore pressure accumulation in marine sediment due to water waves, Research Report No.R868, The Univ. of Sydney, Australia,28pp..
  14. Jeng, D.S., Zhou, X.L., Luo, X.D., Wang, J.H., Zhang, J. and Gao, F.P. (2010). Response of porous seabed to dynamic loadings, Geotechnical Engineering Journal of the SEAGS & AGSSEA, 41(4).
  15. Kianoto, T. and Mase, H. (1999). Boundary-layer theory for aniso tropic seabed response to sea waves, J. of Waterway, Port, Coastal and Ocean Eng., ASCE, 125(4), 187-194. https://doi.org/10.1061/(ASCE)0733-950X(1999)125:4(187)
  16. Lee, K.W., Baek, D.J., Kim, D.S., Kim, T.H. and Bae, K.S.(2013). 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, 26(1), 49-64. https://doi.org/10.9765/KSCOE.2014.26.1.49
  17. Lee, K.W., Park, J.H., Cho, S. and Kim, D.S.(2013). Numerical simulation of irregular airflow in OWC wave generation system considering sea water exchange, Journal of Korean Society of Coastal and Ocean Engineers, 25(3), 128-137. https://doi.org/10.9765/KSCOE.2013.25.3.128
  18. Li, J. and Jeng, D.S. (2008). Response of a porous seabed around breakwater heads, Ocean Eng., 35, 864-886. https://doi.org/10.1016/j.oceaneng.2008.01.021
  19. Madsen, O.S. (1978). Wave-induced pore pressure and effective stresses in a porous bed, Geotechnique, 28, 377-393. https://doi.org/10.1680/geot.1978.28.4.377
  20. Mase, H., Sakai, T. and Sakamoto, M. (1994). Wave-induced porewater pressures and effective stresses around breakwater, Ocean Eng., 21(4), 361-379. https://doi.org/10.1016/0029-8018(94)90010-8
  21. McDougal, W.G., Tsai, Y.T., Liu, P.L.-F. and Clukey, E.C. (1989). Wave-induced pore water pressure accumulation in marine soils, J. of Offshore Mechanics and Arctic Eng., ASME, 111(1), 1-11. https://doi.org/10.1115/1.3257133
  22. 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 J. of the Royal Astrological Society, 66, 597-631. https://doi.org/10.1111/j.1365-246X.1981.tb04892.x
  23. Mitsuyasu, H. (1970). On the growth of spectrum of wind-generated waves(2)-spectral shape of wind waves at finite fetch, Proc. Conf. on Coastal Eng., JSCE, 1-7 (in Japanese).
  24. Miyamoto, J., Sassa, S. and Sekiguchi, H. (2004). Progressive solidification of a liquefied sand layer during continued wave loading, Geotechnique, 54(10), 617-629. https://doi.org/10.1680/geot.2004.54.10.617
  25. MOLIT (2010). Final report about prevention technology for coastal erosion.
  26. Okusa, S. (1984). Marine geotechnology state-of-the-art, Proceedings of the JSCE, 346, 13-21 (in Japanese).
  27. Okusa, S. (1985). Wave-induced stresses in unsaturated submarine sediments, Geotechnique, 32(3), 235-247.
  28. Oumeraci, H. (1994). Review and analysis of vertical breakwater failures and lessons learned, Coastal Engineering, 22, 3-29. https://doi.org/10.1016/0378-3839(94)90046-9
  29. Ozutsmi, O., Sawada, S., Iai, S., Takeshima, Y., Sugiyama, W. and Shimasu, T. (2002). Effective stress analysis of liquefactioninduced deformation in river dikes, J. of Soil Dynamics and Earthquake Eng., 22, 1075-1082. https://doi.org/10.1016/S0267-7261(02)00133-1
  30. Sakakiyama, T. and Kajima, R. (1992). Numerical simulation of nonlinear wave interaction with permeable breakwater, Proceedings of the 22nd ICCE, ASCE, 1517-1530.
  31. Sassa, S. and Sekiguchi, H. (1999). Analysis of wave-induced liquefaction of beds of sand in centrifuge, Geotechnique, 49(5), 621-638. https://doi.org/10.1680/geot.1999.49.5.621
  32. Sassa, S. and Sekiguchi, H. (2001). Analysis of wave-induced liquefaction of sand beds, Geotechnique, 51(12), 115-126. https://doi.org/10.1680/geot.2001.51.2.115
  33. Sassa, S., Sekiguchi, H. and Miyamoto, J. (2001). Analysis of progressive liquefaction as a moving-boundary problem, Geotechnique, 51(10), 847-857. https://doi.org/10.1680/geot.2001.51.10.847
  34. Sawada, S., Ozutsumi, O. and Iai, S. (2000). Analysis of liquefaction induced residual deformation for two types of quay wall: analysis by "FLIP", Proceedings of the 12th World Conference on Earthquake Eng.(Auckland), 2486.
  35. Seed, H.B. and Rahman, M.S. (1978). Wave-induced pore pressure in relation to ocean floor stability of cohesionless soil, Marine Geotechnology, 3(2), 123-150. https://doi.org/10.1080/10641197809379798
  36. Seed, H.B., Martin, P.O. and Lysmer, J. (1975). The generation and dissipation of pore water pressure during soil liquefaction, Report EERC 75-26, Univ. of California, Berkeley, California.
  37. Sekiguchi, H., Kita, K. and Okamoto, O. (1995). Response of poroelastoplastic beds to standing waves, Soil and Foundations, 35(3), 31-42. https://doi.org/10.3208/sandf.35.31
  38. Sumer, B.M. and Fredsoe, J. (2002). The mechanics of scour in the marine environment, World Scientific.
  39. Tsai, C.P. and Lee, T.L. (1995). Standing wave induced pore pressures in a porous seabed, Ocean Engineering, 22(6), 505-517. https://doi.org/10.1016/0029-8018(95)00003-4
  40. Tsuruya, H. and Krezume, T. (1990). Study on fluidization and floating of bottom in surf zone. Proceedings of Coastal Engineering, JSCE, 37, 289-293 (in Japanese). https://doi.org/10.2208/proce1989.37.289
  41. Ulker, M.B.C, Rahman, M.S. and Guddati, M.N. (2010). Waveinduced dynamic response and instability of seabed around caisson breakwater, Ocean Eng., 37, 1522-1545. https://doi.org/10.1016/j.oceaneng.2010.09.004
  42. Yamamoto, T., Koning, H., Sllmejjer, H. and Van Hijum, E. (1978). On the response of a poroelastic bed to water waves, J. of Fluid Mechanics, 87, 193-206. https://doi.org/10.1017/S0022112078003006
  43. 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., 85, 72-86. https://doi.org/10.1016/j.coastaleng.2013.08.003
  44. Yuhi, M. and Ishida, H. (2002). Simplified solution of waveinduced seabed response in anisotropic seabed, J. of Waterway, Port, Coastal and Ocean Eng., ASCE, 128(1), 46-50. https://doi.org/10.1061/(ASCE)0733-950X(2002)128:1(46)
  45. Zen, K and Umehara, Y. (1986). Liquefaction damage of the foundation of the breakwater against approaching waves, Proceedings of the Foundation of Marine Structure, 2, 225-232 (in Japanese).

Cited by

  1. Simulation of Solitary Wave-Induced Dynamic Responses of Soil Foundation Around Vertical Revetment vol.26, pp.6, 2014, https://doi.org/10.9765/KSCOE.2014.26.6.367
  2. Bore-induced Dynamic Responses of Revetment and Soil Foundation vol.27, pp.1, 2015, https://doi.org/10.9765/KSCOE.2015.27.1.63