Seabed Instability due to Flow Liquefaction in the Fraser River Delta

• Author(s) / Creator(s)

  • Robertson, P. K.
  • Morgenstern, N. R.
  • Chillarige, A. V.
  • Christian, H.

• Abstract: Liquefaction failures of loose sand deposits can be a major concern for the stability of coastal structures. an investigation to evaluate the possible contributions of different triggering mechanisms in a major liquefaction failure that occurred in 1985 at the mouth of the Main Channel of the Fraser River has been carried out using steady-state concepts. Potential triggering mechanisms for initiating the 1985 liquefaction flow slide, such as sedimentation, surface waves and low tides are evaluated. The analysis shows that rapid sedimentation generates shear stresses on the slope but may not initiate flow liquefaction failures. The evaluation of the effect of surface waves in causing deep-seated liquefaction flow slides indicates that no significant pore-water pressures accumulate due to the surface waves in the region. Low tides cannot initiate failure in submerged, fully saturated sands. However, gas induces desaturation of the sediment, which can induce residual pore pressures in the sediments during low tides. It is postulated that the combination of loose sediments, small amounts of gas, and low tides contributes to the triggering of flow liquefaction failures in the delta. These failures lead to retrogressive flow slides.

• Date created

  1997

• Subjects / Keywords

  • Steady state
  • Gaseous sediments
  • Low tides
  • Surface waves
  • Rapid sedimentation
  • Liquefaction

• Type of Item

  Article (Published)

• DOI

  https://doi.org/10.7939/R3KW57M3D

• License

  © 1997 NRC Research Press (Canadian Science Publishing). This version of this article is open access and can be downloaded and shared. The original author(s) and source must be cited.