Piedmont Residual Soil - Anisotropy

[NBRY1]

What would be an appropriate field and/or laboratory test method for determining the permeability/anisotropy of piedmont residual soil;
specifically, the partially weathered zone just above interface with competent rock?

 

[fattdad]

what's the end game?

Anisotropy as it relates to slope stability?
Anisotropy as it relates to time for consolidation?
Anisotropy as it relates to pore pressure dissipation?
Anisotropy as it relates to a flow net in dam design?
Anisotropy as it relates to contamination transport?

I work in the Piedmont of Virginia and have some experiences. I can't think of too many times we drilled into the details of anisotropy in the piedmont. Not that I don't get it, I just haven't thought in those terms in the Piedmont.

Willing to address the topic; however. Just not sure where you are headed?

f-d

ípapß gordo ainÆt no madre flaca!

 

[NBRY1]

Anisotropy of piping layer (kh/kv). How can this best be determined?

 

[fattdad]

So, this is for the benefit of a numerical model?

in addressing piping you clearly need to assess the critical gradient, the head drop in the last cell or two and make the comparison against some safety factor. If the soil is truly anisotropic, you can use a numerical model or you can transform the flow net.

If this is all too complicated, you can also simplify the problem statement, see the scale of the concern and still install a toe drain to allow the exit gradient to occur under confinement.

I will remain unclear on the end game. Is this a dam, retaining wall, shoring system, box culvert? Are there boring logs to make you think of an anisotropic setting? Are you striving to use anisotropy to simplify a layered system of soils, etc.

I enjoy these sort of problems!

f-d

ípapß gordo ainÆt no madre flaca!

 

[cvg]

http://www.slb.com/~/media/files/resources/oilfield_review/ors94/1094/p24_35.pdf