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Residual Shear Strength

Residual Shear Strength

Residual Shear Strength

Is anyone familiar with Tim Starks research on correlations between Atterberg limits and residual shear strenngth in clays?  I stumbled across this reference in an old thread:
ramram2 posts "You can also check out Tim Stark's research in the Geotechnical Journal to use liquid limits, clay fraction and overburden stresses to estimate residual phi angles." in reference to a question about multi reversal shear tests.

This piqued my curiosity.  I've come across a paper by Mesri, et al. titled Residual Shear Strength Mobilized in First-Time Slope Failures (Journal of Geotechnical and Environmental Engineering, Jan-03, Vol 129, Issue 1) which correlates residual strength with PI.  I've found this work to be quite useful in lieu of doing costly and time consuming slow slow shear tests (1 trace/ day!!), ring shears, or multi reversal shears to test the residual strength in the lab.  I'm sure there are several other techniques used throughout the industry to calculate residual strength for long term design.  Thoughts??  Anybody know who Tim Starks is or where I can find out more about his work???  

RE: Residual Shear Strength

Tim Stark teaches at U of Illinois.  He's done some interesting work on clays and residual shear strength going back to his dissertation with Duncan in the 80s.  (That was related to a semi-rapid drawdown slide at a dam in CA.  It slid on a layer of weak slopewash on the abutment.)  Nice guy, and he's always been willing to provide me with info.  You can probably get his phone # from UI's web site.

A number of similar correlations have been published over the years, but they all seem to boil down to Phi-resid vs PI or Phi-resid vs LL. Deere published one of each in the 70s (sorry, but my papers are buried so I don't have the exact references), and I think Frank Townsend did also.  

USBR lab data (unpublished?) for PIs between 8 and 50 show Phi'resid ~ 28 deg - 0.34 PI, but the data set was pretty small so don't take that too seriously.

RE: Residual Shear Strength


Stark, T.D. and H.T. Eid, "Drained residual strength of cohesive soils," ASCE JGE May 1994, pp. 856-871.

Same guys, "Slope stability analyses in stiff fissured clays," JGGE April 1997, pp. 335-343.

RE: Residual Shear Strength

The guy Deere that you mentioned, is he the same Deere that first proposed use of the rock quality designation (RQD) in 1967?

Thanks for the references.

RE: Residual Shear Strength

Right, Don Deere.

RE: Residual Shear Strength


Check out FHWA/TX-06/1874-01-1, Evaluation of Soil Shear Strength for Slope and Retaining Wall Stability Analysis with Emphasis on Highly Plastic Clays by Stepehn Wright, dated 8-2005.  

RE: Residual Shear Strength

Corkster, could you please elaborate on the source of the Stephen Wright reference and where to track it down?  I couldn't follow the alpha numeric.  

RE: Residual Shear Strength


This report was prepared by the University of Texas at Austin for TEXdot.  You should be able to get a copy through the National Technical Information Service, Springfield, virginia 22171.  Their website is:


Unfortunately, I don't recall where I found this report,  but since it is a FHWA sponsored report, you may also be able to find a copy through their website.

Hope this will get you to it!

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