Coulomb's Earth Pressure Slope Backfill Ka Height

[JR55]

I'm looking at a retaining wall with straight sides and sloped backfill. I've seen the answer alluded to on a couple of posts, but want to confirm.

For sloped backfill considering stability, is the height to be considered the height to the wedge at the edge of the footing? Or is it the same as the wall structural design where the height is the height at the wall and the slope is accounted for in the Ka coefficient?

I'm assuming a Ka calculated using Coulomb's method.

 

[HTURKAK]

The pressure surface is considered to be at the edge of the ftg.

You may look foundation engineering handbooks ( BOWLES etc) or the following doc. ( free ) for more details.









Use it up, wear it out;
Make it do, or do without.

NEW ENGLAND MAXIM

 

[JR55]

Does it make a difference if the footing is buried under a floor surface? This seems to indicate that if the backfill is not directly on the footing then the height should be taken as the height of the wall.