Please Help - Soil Stiffness Parameters

[handex]

Hey guys,
We have been forced to model a propped sheet piled wall in Wallap. The soil is composed of loose sand for the top 1.5m, with medium dense sand below (with a SPT value of 11). In wallap the user must input whether or not the soil is overconsolidated (OC) or normally consolidated (NC).

The difference between the two models is that the OC model assumes the soil has stiffness at the top, whereas the NC model assumes the soil has no stiffness at the top and varies linearly with depth.

I am looking for a way to justify that the medium dense soil which is providing lateral restraint to the toe can be modelled as OC. If its modelled as NC the results are completely unrealistic and completely in excess of what is required in reality.

Cheers

 

[ishvaaag]

The best way would be that the geotechnical report states so is the case; or at least see its contents to see what you have along that line of thought. The nature of the soil is first investigated and then adjudicated to some type. It may be from experience, as you are inclined here to do, but you are asking general proof to third parties, and the best is by test.