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Subsidence estimation of breakwater built on loosely deposited sandy seabed foundation: Elastic model or elasto-plastic model

  • Shen, Jianhua (State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences) ;
  • Wu, Huaicheng (The Second Engineering Company of CCCC Fourth Harbor Engineering Co. Ltd.) ;
  • Zhang, Yuting (Tianjin Research Institute for Water Transport Engineering, M.O.T.)
  • Received : 2016.06.01
  • Accepted : 2016.11.19
  • Published : 2017.07.31

Abstract

In offshore area, newly deposited Quaternary loose seabed soils are widely distributed. There are a great number of offshore structures has been built on them in the past, or will be built on them in the future due to the fact that there would be no very dense seabed soil foundation could be chosen at planed sites sometimes. However, loosely deposited seabed foundation would bring great risk to the service ability of offshore structures after construction. Currently, the understanding on wave-induced liquefaction mechanism in loose seabed foundation has been greatly improved; however, the recognition on the consolidation characteristics and settlement estimation of loose seabed foundation under offshore structures is still limited. In this study, taking a semi-coupled numerical model FSSI-CAS 2D as the tool, the consolidation and settlement of loosely deposited sandy seabed foundation under an offshore breakwater is investigated. The advanced soil constitutive model Pastor-Zienkiewics Mark III (PZIII) is used to describe the quasi-static behavior of loose sandy seabed soil. The computational results show that PZIII model is capable of being used for settlement estimation problem of loosely deposited sandy seabed foundation. For loose sandy seabed foundation, elastic deformation is the dominant component in consolidation process. It is suggested that general elastic model is acceptable for subsidence estimation of offshore structures on loose seabed foundation; however, Young's modulus E must be dependent on the confining effective stress, rather than a constant in computation.

Acknowledgement

Supported by : National Natural Science Foundation of China

References

  1. Chatterjee, S., Yan, Y., Randolph, M.F., White, D.J., 2012. Elastoplastic consolidation beneath shallowly embedded offshore pipeline. Geotech. Lett. 2, 73-79. https://doi.org/10.1680/geolett.12.00031
  2. Chatterjee, S., Randolph, M.F., White, D.J., 2013. .Coupled consolidation analysis of pipe-soil interactions. Can. Geotech. J. 50, 609-619. https://doi.org/10.1139/cgj-2012-0307
  3. Jeng, D.-S., Ye, J.H., 2012. Three-dimensional consolidation of a porous unsaturated seabed under rubble mound breakwater. Ocean. Eng. 53, 48-59. https://doi.org/10.1016/j.oceaneng.2012.06.004
  4. Krost, K., Gourvenec, S.M., White, D.J., 2010. Consolidation around partially embedded seabed pipelines. Geotechnique 1-7.
  5. Lade, P.V., Bopp, P.A., 2005. Relative density effects on drained sand behavior at high pressures. Soils Found. 45 (1), 1-14. https://doi.org/10.3208/sandf.45.1
  6. Lade, P.V., Nelson, R.B., 1989. Modeling the elastic behavior of granular materials. Int. J. Numer. Anal. Method Geomech. 11, 521-542.
  7. Lee, K.L., Seed, H.B., 1967. Drained strength characteristics of sands. J. Soil Mech. Found. Div. ASCE 93 (SM6), 117-141.
  8. Pastor, M., Zienkiewicz, O.C., Chan, A.H.C., 1990. Generalized plasticity and the modelling of soil behaviour. Int. J. Numer. Anal. Methods Geomech. 14, 151-190. https://doi.org/10.1002/nag.1610140302
  9. Pastor, M., Chan, A.H.C., Mira, P., Manzanal, D., Fernndez, M.J.A., Blanc, T., 2011. Computational geomechanics: the heritage of olek zienkiewicz. Int. J. Numer. Methods Eng. 87 (1-5), 457-489. https://doi.org/10.1002/nme.3192
  10. Sassa, S., Sekiguchi, H., 1999. Wave-induced liquefaction of beds of sand in a centrifuge. Geotechnique 49 (5), 621-638. https://doi.org/10.1680/geot.1999.49.5.621
  11. Sumer, B.M., Fredsoe, J., Christensen, S., Lind, M.T., 1999. Sinking/floatation of pipelines and other objects in liquefied soil under waves. Coast. Eng. 38 (2), 53-90. https://doi.org/10.1016/S0378-3839(99)00024-1
  12. Wang, G., Xie, Y., 2014. Modified bounding surface hypoplasticity model for sands under cyclic loading. J. Eng. Mech. ASCE 140 (1), 91-101. https://doi.org/10.1061/(ASCE)EM.1943-7889.0000654
  13. Wang, Z.L., Dafalias, Y.F., Shen, C.K., 1990. Bounding surface hypoplasticity model for sand. J. Eng. Mech. 116 (5), 983-1001. https://doi.org/10.1061/(ASCE)0733-9399(1990)116:5(983)
  14. Yasufuku, N., Murata, H., Hyodo, M., et al., 1991. A stress-strain relationship for anisotropically consolidated sand over a wide stress region. Soils Found. 31 (4), 75-92. https://doi.org/10.3208/sandf1972.31.4_75
  15. Ye, J.H., 2012. Numerical modeling of consolidation of 2-D porous unsaturated seabed under a composite breakwater. Mechanika 18 (4), 373-379.
  16. Ye, J.H., Jeng, D.-S.,Wang, R., Zhu, Ch-Q., 2015. Numerical simulation of the wave-induced dynamic response of poro-elastoplastic seabed foundations and a composite breakwater. Appl. Math. Model. 39, 322-347. https://doi.org/10.1016/j.apm.2014.05.031
  17. Ye, J.H., Wang, G., 2015. Seismic dynamics of offshore breakwater on liquefiable seabed foundation. Soil Dyn. Earthq. Eng. 76, 86-99. https://doi.org/10.1016/j.soildyn.2015.02.003
  18. Ye, J.H., Jeng, D.-S., Chan, A.H.C., 2012. Consolidation and dynamics of 3D unsaturated porous seabed under rigid caisson breakwater under hydrostatic pressure and wave. Sci. China Technol. Sci. 55 (8), 2362-2376. https://doi.org/10.1007/s11431-012-4888-4
  19. Ye, J.H., Jeng, D.-S., Wang, Ren, Zhu, Ch-Q., 2013. Validation of a 2D semicoupled numerical model for fluid-structures-seabed interaction. J. Fluids Struct. 42, 333-357. https://doi.org/10.1016/j.jfluidstructs.2013.04.008
  20. Zhao, Y.H., Zhu, J.G., Zhang, Z.L., Liu, X., 2011. A compression model for cohesionless soils. Rock Soil Mech. 32 (10), 1033-1038.
  21. Zienkiewicz, O.C., Chan, A.H.C., Pastor, M., Schrefler, B.A., Shiomi, T., 1999. Computational Geomechanics with Special Reference to Earthquake Engineering. John Wiley and Sons, England.