Determining axial loading for CU tests

[tpk72]

I apologize for posting such a basic question, but what is the proper way to determine the axial loading for CU triaxial tests?


Thank you

 

[moe333]

Do you mean the consolidation stress?

 

[Jalthi]

Check out this forum.

http://www.eng-tips.com/viewthread.cfm?qid=272835&page=1

 

[fattdad]

it typically requires three "tests" to provide one failure envelope (i.e., get a friction angle). I'd certainly consolidate the sample to the existing overburden pressure. Then the further answer relates more to the anticipate stress path. If you are designing a cut slope, you'd certainly want to consolidate to a lower stress. If you are designing for additional loads (i.e., retaining wall or road embankment) you'd want to consolidate to a higher stress. The third "test" can follow the trend or bracket the existing overburden pressure.

Now the question is, "What defines failure for each 'test'?" Check the ASTM for further confusion. . .

f-d

¡papá gordo ain’t no madre flaca!

 

[paganel]

And do remember the preconsolidation stress the sample experienced.It could cause different behaviour for the sample. A obvious overconsolidated sample commonly will show a higher C' and lower Phi' compared to its normal consolidated peer.
Suggest do an oedometer test before carry out any triaxial test.