f-d,
Right, there is merit to not considering cohesion. More than just conservatism I mean. You bring up a point I would like to explore.
The removal of cohesive strength above a "tensile crack" and application of cohesive strength below appears to the the approach suggested by soils mechanics...
VAD, I think I understand your scenario.
Your vertical cut gets to use cohesive strength and can stay vertical for some time, although OSHA will have problems with you if you have a high vertical cut. (if you give your excavation wall enough time, the vertical face will begin to develop...
Thanks for the input fattdad. By stepping back 4 feet on a 12' wall before stepping up 1H:2V; a conservative 45 degree failure wedge would intersect the granular/cohesive boundary 8 feet above the wall base. Given a triangular stress distribution with depth, almost 90% of the pressures being...
Sorry for the long post with my question. I've got some background in my question so basic soil mechanics won't need repeating.
It is common to use granular backfill behind retaining walls instead of cohesive backfill to reduce wall pressures. Reasoning being that a higher friction angle...
