StructEng101
Structural
- Dec 8, 2020
- 1
An engineer has submitted drawings to my office for review and approval. They are proposing an MSE wall using 2'x2'x6' blocks and a geogrid reinforcing product extending back from the face of the wall into the reinforced soil zone. It is an approximately 10 foot tall wall at its tallest with the geogrid extending six feet from the back face of the wall. I take quite a few exceptions to his design, but I want to get gather some opinions on the proposed backfill. The engineer is proposing to backfill the entire reinforced soil zone with 2-1/2" crushed stone. This geogrid product doesn't seem to be tested with such a large stone. The RFid (installation damage reduction factor) for a 3/4" stone is 1.25, for sand is 1.10, and for silt/clay is 1.05. What would it be for 2-1/2" stone? I'm afraid backfilling this stone over the geogrid is going to tear it apart. Does anyone have any watch-its for using such a large stone in the reinforced soil zone? The engineer is assuming an angle of internal friction of 40 degrees. Is this valid? Is their compaction that you would need to achieve this?