Yes, you are correct. With soft soils, you just can't hold much earth back. And that makes logical sense, too. Now, that presumes you're analyzing it as a retaining wall with a spread footing. Why not consider it like a sheet pile and ignore the footing and see how far you get? I'm not saying you'll end up better off - I don't do sheet piles, so I don't have a good feel for them - but it's another avenue to pursue. Also, you might consider micropiles under the footings.
Jordan
Michel wrote:
Thank you all for the input on proportioning. However, my confusion persists.
There seems to be a practical limit on retained soil ht. when constrained to 1,000 psf max. allow. soil bearing press. My restrained ht. is about 8'. I just wanted to verify this.
-Michel