×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

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

Jobs

compaction to achieve a bearing pressure of 70KN/M2

compaction to achieve a bearing pressure of 70KN/M2

compaction to achieve a bearing pressure of 70KN/M2

(OP)
The uderneath concrete slab is to be treated to have a bearing pressure of 70KN/M2. The organic soil has been removed and replaced with broken stones with lots of fines. This was compacted using a roller. The ground is further required to be raised by 200mm to get to he formation level to receive the concrete slab.

What type of stone and roller/compactive effort are required to achieve the 70KN/M2.

Thanks
Yamen

RE: compaction to achieve a bearing pressure of 70KN/M2

First off, 70 kPa is not all that much - unless you are supporting the slab on soft clayey soil - in which case your 500 mm of so of "base" is of little use.  I am not sure that the 70 kPa is dead and live load or just dead load.
   Presuming of course, that you have "good" soil exposed (and it is to depth) after removing the organics, one usually would compact the underside fill to something like 95% modified Proctor dry density (I like to use modified when I have load bearing - footings, slabs, etc.)  
   To gain an appreciation of how little 70 kPa bearing is - take a look at a chart of SPT-"N" value vs large 'footing'.  Divide by 5, say to keep "settlement" to 5mm or so - and you will see that the "N" value would only need to be 20 or so - and this would be achievable under compaction noted above (and, I do realize this is for "extensive" depth - but to gain the appreciation it is an analogy that can be studied).   

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!


Resources