I'm not sure I'd use L-Pile for this. L-pile was originally developed for long-slender steel pipe piles offshore...additional research since then, but pretty specific to these constraints.
Another approach may be to use a combination of over-excavation, use of a geotextile (fabric and/or grid), and backfilling with structural fill.
Cheers,
Z
What are your thoughts regarding large diameter shafts and using L-Pile? My understanding is that L-pile is more geared for "smaller" diameter shafts (slender elements). Any thoughts on the strain-wedge method of analysis?
sdz