soils "Calculation of phreatic surface in an earth dam"

[IceBreakerSours]

Dear members,

I am trying to understand how soil consolidation analysis works using the example entitled "Calculation of phreatic surface in an earth dam" in the ABAQUS Examples Manual (specifically, phreaticsurf_cpe8rp.inp). I noticed a few statements in the example that I did not quite follow:

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[li]

Since the natural boundary condition in the pore fluid flow formulation provides no flow of fluid across a surface of the model, no further specification is needed on this surface.

Do I simply leave a surface alone if it is impermeable? Don't I need to assign a zero pore pressure or zero permeability and void ratio boundary condition?
[/li]

[li]

the default assumption is used for the partially saturated permeability: that it varies as a cubic function of saturation, decreasing from the fully saturated value to a value of zero at zero saturation.

Where is this set? I do not see any values in the "Saturation Dependence" (which is where I assumed this variability would be defined) table.
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[li]

The initial void ratio of the earth material is 1.0

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I see the initial void ratio = 1.0 defined in the *Initial Conditions, Type=Ratio line of the INP. But then, what does the "Void Ratio" option in the Permeability (material behavior) stand for?
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These questions reflect the fact that I have barely begun to understand "soil consolidation" theory and modeling both. I'd appreciate any help.

Thanks.

http://www.eng-tips.com/faqs.cfm?fid=376

http://www.eng-tips.com/faqs.cfm?fid=1083