Swell Potential with Foundations

[JohnnyB_]

Hello -

Does anyone have an example calculation of swell/consolidation potential for a foundation based on a swell/consolidation test? I assume this would include the boussinesq bulb per layered depth as well as the swell % and psf of the clay.

I appreciate any input.

 

[geotechguy1]

There is some decent material on the vulcanhammer website

https://vulcanhammer.net/2018/11/28/van-der-merwes-method-adapted-for-si-units/

 

[MTNClimber]

Swell(%) x Depth of Wetting x Reduction Factor = Potential Swell

Depth of wetting is subjective. It's based on land use and the engineer's experience. I've seen 8-12 feet below finished grade for a site without irrigation. 12-16 feet for commercial sites, 21-30 feet for residential. Don't forget to ignore any potential swell above the footing or basement slabs since that won't contribute much heave.

Reduction factor: the only firm I worked with that used one put a 0.8 reduction factor to account for the ground not fully saturating like the test sample.

 

[pelelo]

There is a great reference by Nelson and Miller "Expansive Soils", you should review it.

 

[JohnnyB_]

Thanks for all the feedback folks. I appreciate the input.