Coulomb Earth Pressure

[NBRY1]

Can coulomb active earth pressure be greater than 1.0?
For the case:
wall backslope from vertical = 45degree
wall backslope from horizontal = 45 degrees
retained soil backslope = 16 degrees
friction angle = 30
friction between wall and backfill = 14 degrees

I calculate Ka= 1.396

 

[PEinc]

Do you mean that the face of the wall is sloped (battered?) at 45 degrees while the retained soil behind the wall slopes upward at 16 degrees from the top of the wall? How can you have both 16 and 45 degree backslopes?

http://www.PeirceEngineering.com

 

[PEinc]

I didn't run any numbers yet because I want clarification from you. If phi = 0 degrees and the wall is leaning (battered) forward, Ka might be greater than 1.0. If the wall is plumb or leaning (battered) backwards, Ka should be <1.0.

http://www.PeirceEngineering.com

 

[MTNClimber]

I'm having trouble understanding it too. We should be able to provide you with a response if you give us a sketch.

 

[Guest262653]

That's the value I get as well. I enclose my spreadsheet for comparison.

 

[PEinc]

avscorreia, where are your 45 degree backslope, 16 degree slope behind the wall, 14 degree wall friction (I see 13.5 degrees), and 30 degree phi angle? I don't see any of NBRY1's input.

http://www.PeirceEngineering.com

 

[Guest262653]

I'm sorry. I enclosed the file without saving it so it used the previous input... Here it goes again, now properly corrected.

 

[NBRY1]

Attached is wall figure.