A Case Study of Sediment Transport on Trenched Backfill Granular and Cohesive Material due to Wave and Current

  • Received : 2016.04.06
  • Accepted : 2016.05.31
  • Published : 2016.06.30


In this study, after the installation of a subsea pipeline, backfilling was performed in the trenched area. During these operations, a stability problem in the subsea pipeline occurred. The pipeline was directly impacted by environmental loading such as waves and currents that were caused by backfill material when scouring or sediment transport and siltation was carried out. Therefore, this study reviewed whether trenching was necessary, and conducted research into an indigenous seabed property that contains granular soil. A study of cohesive soil was also conducted in order to cross-correlate after calculating the values of the critical Shields parameter relevant to elements of the external environment such as waves and current, and the shear Shields parameter that depends on the actual shearing stress. In case of 1), sedimentation or erosion does not occur. In the case of 2), partial sedimentation or erosion occurs. If the case is 3), full sedimentation or erosion occurs. Therefore, in the cases of 1) or 2), problems in structural subsea pipeline stability will not occur even if partial sedimentation or erosion occurs. This should be reflected particularly in cases with granular and cohesive soil when a reduction in shear strength occurs by cyclic currents and waves. In addition, since backfilling material does not affect the original seabed shear strength, a set-up factor should be considered to use a reduced of the shear strength in the original seabed.



  1. Abbas Moustafa,2012, "Advanced in Geotechnical Earthquake Engineering- Soil Liquefaction and Seismic Safety of Dan and Monuments",ISBN 978-953-0025-6, pp.65-80
  2. Acker, P. and White, W.R., 1973, "Sediment Transport : new approch and anaysis", Journal of the Hydraulics Division, ASCE, 99(11), pp. 2041-2060.
  3. Acker, P.,1972, "Sediment Transport in Channels : An Alternative Approch", Report INT 102, Hydraulic Research Station, Wallingford, England.
  4. Bagnold, R.A., 1966, "An Approch to the sediment transport problem from general physics", U.S. Geological Survey Prof. Paper, pp. 422-I
  5. Bailard, J.A., 1981, "An Energetics total load sediment transport model for a plane sloping beach", Journal of Geophysical Research, Vol, pp.10938-10954
  6. Chih-Hsin Vhang, Leen-Kwei Chien and et al, 2004, "3-D Liquefaction Potential analysis of Seabed at nearshore Area", Journal of Marine Science ant Technology, Vol.,12, No.3 pp.141-151.
  7. Daniel B. Chu, Jonathan P. Stewari, et al, 2008, "Cyclic Softening of Low-Plasticity Clay and Its Effect on Seismic Foundation Performance", Journal of Geotechnical and Environmental Engineering, pp.1595-1608
  8. EM 1110-2-1100(Part III), 2002, Sediment Transport outside the surf zone
  9. EM 1110-2-1100(PartIII), 2002, Longshore Sediment Transport
  10. FHWA NHI-05-042, 2006, "Design and Construction of Driven Pile Foundations" pp.9-179
  11. Ken Been, Abdelfettah Fredj and George Comfort, 2011, "Pipeline strains in soft clay backfill subject to ice gouging" Journal of pipeline engineering, Vol.10, No.2, pp.91
  12. Lien-kwei Chien, C.H.Chang and et al.,2003,"The Mechanism Analysis of Wave-induced Seabed Liquefaction", Proceeding of the thirteen International offshore and polar engineering conference, pp.445-452
  13. Madsen, O.S., 1994, "Spectral Wave-current bottom boundary layer flows", 24th Internationa Coference Coastal Engineering Research Council/ASCE
  14. Recommended Practice DNV-RP-E303,2005, "Geothechnical design and installation of suction anchors in clay" pp.12-13
  15. Recommended Practice DNV-RP-F110,2007, "Global Buckling of Submarine Pipeline" pp.49.
  16. Scheffner, N.W., 1996, "Systematic analysis of long-term fate of disposed dredged material", Journal of waterway, port, coastal and Ocean Engineering, pp.127-133
  17. T.L.Youd and I.M. Idriss,2001,"Liquefaction Resistance of Soils:Summary Report from the 1996 NCEER and 1998 NCEER/NSF Workshop on Evaluation of Liquefaction Resistance of Soils", Journal of Geotechnical and Geoenvironmental Engineering, pp297-313