Undrained Shear Stength
Undrained Shear Stength
(OP)
I am trying to get a grip on soil properties. I have seen many tables listing typical phi, gamma and E values for different soil types. However I have not seen one for Cu. Does such a table exist? Does anyone have a link?
Thanks!
SS
Thanks!
SS





RE: Undrained Shear Stength
There is no typical Cu for cohesive materials. Some are soft, some are stiff. And you never know for sure what the shear strength is until you sample and test them. That's why we perform investigations.
Jeff
RE: Undrained Shear Stength
You may, however, find some generalized curves for c/p, i.e., undrained shear strength normalized for insitu effective stress. For design purposes, site specific testing is the way to go as Jeff mentioned.
RE: Undrained Shear Stength
RE: Undrained Shear Stength
RE: Undrained Shear Stength
RE: Undrained Shear Stength
I'm sorry that I didn't understand your question right off. I thought you were asking about Cu for different types of soil as in illite-dominated clays vs. lower plasticity kaolinte type clays, for example. I don't know how he does it, but BigH always seems to understand exactly what is being asked! Good job once again, BigH!
RE: Undrained Shear Stength
See Chuck Ladd's Terzaghi Lecture:
Ladd, C.C. (1991), "Stability Evaluation During Staged Construction," the 22nd Terzaghi lecture, ASCE Journal of Geotechnical Engineering, vol.117, no. 8, pp. 1540-615.
He includes a lot on c/p ratios, and gives typical values. It's a good summary of undrained strength issues in general (in addition to SHANSEP), including the importance of triaxial compression vs simple shear vs triaxial extension in the undrained strength, i.e., c/p is not a constant for a given clay - it varies considerably with stress path
Better yet, get a vane or cone, and remember it's just a bunch of dirt and we can't get terribly precise in trying to determine its engineering properties.