what is mobilized shear strength?

[Cryopatra]

Hi all

To correct shear vane test results ( between 48 and 70 kPa for a firm slightly sandy CLAY), I need to divide by the mobilized shear strength. How do I find it?

Then I can correlate the corrected parameter with plastcity index. How do I derive soil parameters (unit weight, cohesion,...) from PI?

New to the job....

 

[jdonville]

Cryopatra,

See ASTM D 2573 for data reduction for field vane tests.

As for deriving other parameters from PI, you can use empirical relations for effective phi. PI, compbined with other indices can be used to develop other synthetic parameters, such as preconsolidation pressure. For unit weight, you will need to test recovered samples directly. The vane test will give you undrained cohesion and sensitivity.

Based on the information you are asking for, I get the impression that you are not a geotechnical engineer. If this is the case, please don't dabble - get a local geotech who is familiar with the soils in your area to assist you. If you are a geotechnical engineer, perhaps you should be asking a more experienced and licensed geotechnical engineer with your firm before posting here.

Jeff


Jeffrey T. Donville, PE
TTL Associates, Inc.

http://www.ttlassoc.com