Can i use undrained value for slope stability?(application of UU test)
Can i use undrained value for slope stability?(application of UU test)
(OP)
Hi,
Can i use the cu value (phi=0) obtained from the UU test for slope stability analysis instead of using c' value from CIU test?
If no, why it is not possible to use the undrained strength for slope stability calculation.
I have road embankment failure/road foundation failure and only UU test result.
Thank you
Can i use the cu value (phi=0) obtained from the UU test for slope stability analysis instead of using c' value from CIU test?
If no, why it is not possible to use the undrained strength for slope stability calculation.
I have road embankment failure/road foundation failure and only UU test result.
Thank you





RE: Can i use undrained value for slope stability?(application of UU test)
RE: Can i use undrained value for slope stability?(application of UU test)
So if the road was built for almost 8 years, then i guess the right way is to use the c' and phi' value for the stability analysis. Even if it is clayey material?
The road seems to have settlement issues since open to public 8 years ago, can we assume that the PWP already equalise?
Thank you
RE: Can i use undrained value for slope stability?(application of UU test)
Based on your post, you need to be working with the more experienced engineer to determine the best way to handle this situation.
Beginning of rant: By the way, the money spent on running UU tests was wasted. I see this sort of thing on a regular basis, and frankly there is no reason for it. Engineers need to think about what kind of data they need before going to the field, leave alone before assigning laboratory testing. End of rant.
Mike Lambert
RE: Can i use undrained value for slope stability?(application of UU test)
Thank you GeoPaveTraffic.. yes agreed on the rant. I'm a junior n just assigned with this case with only UU test data.
i assumed now 1D-conso and CIU test results are important for road failure/settlement for road that had been constructed long time ago.
RE: Can i use undrained value for slope stability?(application of UU test)
RE: Can i use undrained value for slope stability?(application of UU test)
https://www.usbr.gov/ssle/damsafety/risk/BestPract...
RE: Can i use undrained value for slope stability?(application of UU test)
RE: Can i use undrained value for slope stability?(application of UU test)
RE: Can i use undrained value for slope stability?(application of UU test)
Best way to evaluate fully-softened shear strength is to push the soil through the No. 40 sieve (without air drying), hydrate the soil to its liquid limit, mold it into an odometer and then incrementally consolidate the soil to the target confinement pressure (incremental to minimizing squeezing effects). Run the direct shear and you will have a series of peak strengths on the normally-consolidated sample. Use these peak strengths to get the failure envelope for fully-softened strength. If you capture any cohesion, ignore it in design. If the stress-strain curve also shows a residual strength, that'd be the same residual strength you'd obtain from an intact sample.
There is a citation at CGPR (Center for Geotechnical Practice and Research - Virginia Tech) on these matters. Tim Stark likes the rotational shear for similar conclusions.
f-d
ípapß gordo ainÆt no madre flaca!
RE: Can i use undrained value for slope stability?(application of UU test)