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


White Paper - The Criticality of the E/E Architecture
Modern vehicles are highly sophisticated systems incorporating electrical, electronic, software and mechanical components. Mechanical systems are giving way to advanced software and electronic devices, driving automakers to innovate and differentiate their vehicles via the electric and electronic (E/E) architecture. As the pace of change accelerates, automotive companies need to evolve their development processes to deliver and maximize the value of these architectures. Download Now
White Paper - Model Based Engineering for Wire Harness Manufacturing
Modern cars, trucks, and other vehicles feature an ever-increasing number of sophisticated electrical and electronic features, placing a larger burden on the wiring harness that enables these new features. As complexity rises, current harness manufacturing methods are struggling to keep pace due to manual data exchanges and the inability to capture tribal knowledge. A model-based wire harness manufacturing engineering flow automates data exchange and captures tribal knowledge through design rules to help harness manufacturers improve harness quality and boost efficiency. Download Now
White Paper - Modeling and Optimizing Wire Harness Costs for Variation Complexity
This paper will focus on the quantification of the complexity related costs in harness variations in order to model them, allowing automated algorithms to optimize for these costs. A number of real world examples will be provided as well. Since no two businesses are alike, it is the aim of this paper to provide the foundational knowledge and methodology so the reader can assess their own business to model how variation complexity costs affect their business. 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