compaction in small earth water storages

[Robbo100]

G'day,

I have some minor problems with compaction and major problems with moisture content. See the attached summary.

Over such a small area the OMC varied from 11% to 50%. It was impossible therefore to compare a nuclear gauge reading to a typical OMC. By the time the laboratory results came back - the location was buried by another metre of wall.

The problem was addressed by beating the hell out of it with rollers on the basis of a qualitative indication from field density. Such that compaction was almost achieved but moisture contents were all over the place.

I am being told now that moisture content at placement is critical to performance because of permeabilty. Can't see it myself. If you have 2 samples at the same density - one with 10% water and zero air voids and one with 5% water - both still have 25% voids.

I understand there might be some unspecified issues with elasticity? Other than that the material has a solid fines content and is very plastic.

 

[fattdad]

For a given density, hydraulic conductivity for the same soil sample can vary by two orders of magnitude depending on compaction moisture content (dry side v. wet side of optimum). Reference work by Jim Mitchell along with Hoooper and Campenella (ASCE, Vol. 91, No. SM-4, July 1965, pp. 41-65). Use your interlibray loan.

f-d

¡papá gordo ain’t no madre flaca!

 

[Robbo100]

Hi,

The changes are due to structural differences due to particle dispersion - more dispersion with wetter materials and with more compactive effort.

So you are right - but it is not the total voids but the size of the voids. This is addressed in the uplodaded document. A good reference.

Thanks
Rob