×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Contact US

Log In

Come Join Us!

Are you an
Engineering professional?
Join Engine-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!

*Engine-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

plate bearing tests - can you derive soil density and/or friction angles from these?

plate bearing tests - can you derive soil density and/or friction angles from these?

plate bearing tests - can you derive soil density and/or friction angles from these?

(OP)
I have some plate bearing test results giving the Ult bearing capacity for the subgrade which a piling platform will be formed upon.
How do I equate these values back to giving me a bulk unit weight and a friction angle so I can design the piling platform?

Could i do a cross comparison calc and back fit using Terzaghi or Meyerhof bearing equations? I’m only after an approximation
So we know the Qult, diameter of circular plate and we know this is 6F2 material on top of made ground. So if I fix the bulk unit weight at say 20kn/m3 and then alter the friction angle to achieve a similar Qult as the Plate Bearing Tests?

Would this work and is comparable?

RE: plate bearing tests - can you derive soil density and/or friction angles from these?

I do not know of any correlation from PMT to unit weight.

The correlation mentioned for PMT to friction angle references the Hughes et al 1977 Pressuremeter test in sands article.

RE: plate bearing tests - can you derive soil density and/or friction angles from these?

It amazes me that so many still do plate load tests where in situations that are, at least in my view, not applicable. The tests described here are for a piling platform. What is the size of the platform? What is the effective depth to which the plate load test is applicable? The latter - for no more than 1000 mm but typically 600 mm (2 x plate diamter, typically 300 mm). The former, being many metres in size - 20 to 30? or more? - affects the ground to depths of many many metres. Is the plate load test applicable? I think not. What if 2-1/2 m down, the soil became a soft clay - and not the surficial desiccated crust of the clay? What if? . . . something I was always asked when trying to explain things like "What is the probability of the 200 year earthquake happening in the 2 month construction window?" - my mentor's response? "What if?"

Case in point. In India, the Calcutta clay plains, the stratigraphy consists of about 6 m of very soft clay (N = 0 to 2, Su = 15 to 20 kPa) overlying firm (medium stiff) to stiff clay. As a general rule, ground improvmenet - pvd with stage loading, were needed to construct the MSE bridge approach embankments. At one location where it was a "built up" ground, a structural engineer said "No need. We'll do a plate load test." He did the test and said that the site was good for 350 kPa bearing pressure so no problem building the MSE wall "full height". Yours truly fought to do the ground improvement; and won. The first 4 m layer of the MSE embankment was placed and the embankment settled 400 mm. Did the plate load test show this? No. The plate load test was done in a 2 m thick built up ground and only tested the built up ground - not the soil "at depth" which would be stressed by the embankment. So my word of advice - unless for pavement design (thin layers of subbase/base) - do not rely on plate load tests except in very well defined situations.

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 Engine-Tips Forums free from inappropriate posts.
The Engine-Tips staff will check this out and take appropriate action.

Reply To This Thread

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

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


Resources

Low-Volume Rapid Injection Molding With 3D Printed Molds
Learn methods and guidelines for using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs and lead time. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Download Now
Design for Additive Manufacturing (DfAM)
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a part’s function at the center of their design considerations. Download Now
Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. Download Now

Close Box

Join Engine-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 Engine-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close