What relationships are used to estimate the Critical Shear Stress values?
Depending on the quality of inputs and nature of the sediment, several relationships are used to predict Critical Shear Stresses. The details and supporting references are given in the onCALCULATION document. The relationships include: • Where the consolidation is known and substantial, the CSS is set equal to the value of the Shear Strength. • For unconsolidated granular sediments a compilation using hundreds of experimental results from the field and laboratories suggests a linear relationship with phi grain size. • For unconsolidated fine-grained sediments (>5phi grain size) where there is information on density or porosity, the CSS is based on the density using published relationships. • For unconsolidated fine grained sediments without information on density or porosity, a general value is used. <>No regard to the effects of bio-consolidation or bioturbation is made.
