Consolidation Testing of Recompacted Soils

[EireChch]

Is there ever a need to do a consolidation test on re-compacted soils?

My only thought is for situations say for where a cohesive soil is used as structural fill ? But typically when you compact a cohesive fill it is to some specification (i.e. 98%DD) and therefore settlement shouldn't be an issue?

 

[emmgjld]

I have done quite a few consolidation tests on re-compacted soils. Mostly in-house, but was able to charge for some.
The main reason is to answer the question, how much will the fill, usually of moderate thickness, actually settle or heave? That is a question which is rather common on this board. I feel I have a very good handle on what is to be expected and therefore, I can provide better recommendations and write better specifications.
And yes, even "when you compact a cohesive fill it is to some specification (i.e. 98%DD) and therefore settlement shouldn't be an issue?" you often don't really know until you test. Actually, I assume that most fills will settle, hopefully less that the replaced soils.
As I deal with clayey soils, I have also seen inappropriate compaction specifications which actually created expansive fill beneath foundations, slabs & pavements. A couple of consolidation tests may have alerted the geotechs prior to writing the recommendations.

 

[EireChch]

It wouldnt be all too common though would you think? And Actually, I assume that most fills will settle, hopefully less that the replaced soils., yes i would agree very much. I dont think any engineer would say their fill wont settle. The old we expect minimal settlement statement and just never say what minimal is! .

What way did you compact the test emmgild, did you run proctor test at different moisture contents and then trim the sample for an odeometer ring? In the odeometer test, if you used the same loading (i.e. the expected design loading of the fill) then you could plot strain v MC. That would give you and idea of settlement for different moisture contents.?

 

[oldestguy]

See the discussion at this link, for a similar suspect.

http://www.eng-tips.com/viewthread.cfm?qid=422002