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

Use of saturated Mohr-Coulomb failure criterion and a water table

Use of saturated Mohr-Coulomb failure criterion and a water table

Use of saturated Mohr-Coulomb failure criterion and a water table

Hello all.

I have recently read a report where someone has conducted a slope stability assessment using the rocscience SLIDE software. For this analysis, they defined the material using mohr-coulomb c=40kPa, phi = 25deg which was derived from CU triaxial tests. This test type represents a saturated soil. Therefore, I was surprised to see that they also included a water table.

Now, I am not sure if I am getting confused here, but isn't this double accounting the groundwater within the soil? And if you have MC params from a CU triaxial, you already assume the soil is fully saturated and does not need a water table within the analysis?



RE: Use of saturated Mohr-Coulomb failure criterion and a water table

If you are running an effective stress slope stability analysis, then the water table needs to be included in the analysis because it influences the effective stresses, and thus the shear strength.

Shear strength = c’ + sigma’(tan(phi’))

If you were running a total stress analysis, the water table should not make a difference (a difference in the shear strength) because you are using total stresses.

RE: Use of saturated Mohr-Coulomb failure criterion and a water table

Based on the parameters provided to me this indicates a low plastic clay. Selecting the CU test is an indication of the long term steady state.

As an old engineer told me if you build a dam on soft clay you only need to be concerned for the first two years after construction. If it doesn't fail in the first two years the foundation Clay's have consolidated and gained strength.

The critical case is the end of construction case where all the pore pressure has not dissipated and how that is analyzed. In slope/w I have seen a b-bar used to increase the pore pressure.

RE: Use of saturated Mohr-Coulomb failure criterion and a water table

Thank's all for your replies to my question.

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 - Integrating the Engineering Ecosystem
Aras Innovator provides multiple options for integrating data between systems, depending on the scenario. Utilizing the right approach to meet specific business requirements is vital. These needs range from authoring tools, federating data from various and dissimilar databases, and triggering processes and workflows. Download Now
Research Report - Simulation-Driven Design for SOLIDWORKS Users
In this engineering.com research report, we discuss the rising role of simulation and the paradigm shift commonly called the democratization of simulation. In particular, we focus on how SOLIDWORKS users can take advantage of simulation-driven design through two analysis tools: SOLIDWORKS Simulation and 3DEXPERIENCE WORKS. Download Now
White Paper - Industry 4.0 and the Future of Engineering Education
With industries becoming more automated, more tech-driven and more complex, engineers need to keep their skills and knowledge up to date in order to stay on top of this wave—and to be prepared for the Industry 4.0 future. The University of Cincinnati offers two online Master of Engineering degree programs designed specifically for practicing engineers. Download Now
eBook - The Design Gridlock Manifesto
In this eBook, you’ll learn 6 ways old CAD technology slows your company down and hear how design teams have put those problems to rest. “The Design Gridlock Manifesto” shares first-hand modern CAD experiences from 15 companies around the world. 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