Calculating the effects of Long Term Weathering for Clays

[waisgai]

Can any one refer me to a textbook/paper that discusses a method for calculating the effects of long term weathering on the shear strength of high plasticity clays?
This is for a slope stability analysis, in the long term condition. I generally use a reduction factor of 0.9 on the long term CU shear strength value, however the flood control district is asking for detailed calculations justifying the reduction.

Any help would be greatly appreciated!

 

[fattdad]

I refer you to the publications of Tim Stark (

http://cee.illinois.edu/faculty/timothystark)

I'd use the "fully-softened" shear strength, which is best depicted as the peak strength of normally consolidated re-constituted samples. Tim likes the torsional ring shear device. There are proceedures in the DDS device too.

The Center for Geotechnical Practice and Research (Virginia Tech) hosted a workshop on fully-softened shear strength and Tim was one presenter along with Steve Wright (UTexas). You may want to check out the work of Dr. Wright too.

f-d

¡papá gordo ain’t no madre flaca!

 

[dgillette]

See if Google can find "Evaluation of Soil Shear Strengths for Slope and Retaining Wall Stability Analyses with Emphasis on High Plasticity Clays" which Dr. Wright and others prepared for the Texas highway department and Federal Highway Administration. Should be able to download it legally from one of those agencies, or

http://www.ntis.gov.

Hi fattdad.