Scour assessment in complex marine soils - an evaluation through case examples

Scour in cohesionless soils (i.e. sand or gravel) is relatively well understood. The prediction of scour in cohesive or multi-modal soils (i.e. clay, silt, sand/gravel/clay mixtures) is more complex.
Typically the scour process is much slower; as a result the effect of scour is very much dependent on the period of time that the structure will remain at the site.
This paper describes the application of the Earth Materials approach to estimating scour depth applied to three different case studies. The approach can be applied using information obtained during site investigations but requires good information on soil properties with depth through the seabed.
The method relies on previously calibrated formula for stream power at the seabed, which in the original proposed form theoretically allows scouring to continue even beyond the maximum allowable scour depth in some circumstances.