Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here


Stress ratio of normally consolidated clay

Stress ratio of normally consolidated clay

Stress ratio of normally consolidated clay

Hi all,

Typically the stress ratio (su/σ'v0) for normally consolidated clay is taken in the range of 0.25 to 0.35ish. For several sites where there is no geological explanation for underconsolidation, I have seen ratios as low as 0.20 or even 0.15.

The value of stress ratio is dependent on the mode of shear; 0.25 typically comes from UU triaxial. However, at the sites I mention the stress ratio has also been derived from UU triaxial. I was therefore wondering if anyone knew where this typical 0.25 ratio comes from?

Thanks for any help with the above.

Kind regards,


RE: Stress ratio of normally consolidated clay

LRJ, attached is an extract from Budhu's book which shown in a simple way this correlation. If you take a look at Soil Mechanics in Engineering Practice book from T&P& Mesri (page 167 in the third edition), it explains extensively how this correlation was derived.

RE: Stress ratio of normally consolidated clay

Thanks, Okiryu. The extracts you provided appear very useful.

Does the other book you mention (Soil Mechanics in Engineering Practice, 3rd edition) have something different to what you attached? If so, could you reproduce the derivation here please?

RE: Stress ratio of normally consolidated clay

you can measure Su/p via a series of triaxial tests. Just take a normally consolidated sample and run three CU tests at different confinement pressures.

I'd be more likely to see ratios of 0.2 to 0.25 for the soils I work with.

If you are actually working with overconsolidated samples, you'll get much higher values prior to Pp then it should all revert to typical values.

Jamiolkowski, Turin, Italy is a reference. I think Ladd is prominent in this field too?


ípapß gordo ainÆt no madre flaca!

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login


eBook - Manufacturing the Cars of Tomorrow
In this ebook, we'll explore how additive manufacturing is going to transform the way cars are made. This includes commentary from thought leaders such as Ford's CTO, Ken Washington, Customer case studies of ways 3D printing is being used today, and a variety of part examples where 3D printing is already impacting how automobiles are made. Download Now
White Paper - Smart Manufacturing for Semiconductor
New technologies and approaches present great opportunities for semiconductor manufacturers to achieve high levels of innovation, yield and improvement. This white paper explores some of these cutting-edge technologies and how they can be applied effectively in the semiconductor industry. Read about how Smart Manufacturing is transforming the semiconductor industry. Download Now
White Paper - Analysis and Simulation in Aircraft Structure Certification
Organizations using simulation and analysis tools effectively see the benefits in their ability to achieve certification faster and with drastically less total cost than those who do not maximize these tools. Read this White Paper to learn about how digital tools such as analysis and simulation help in aircraft structure certification. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close