Stabilizing foundation trenches in sandy soil 1

[petrosoft]

I am designing a raft foundation for a small house on silty-sandy soil subject to liquefaction in Northern California. The foundation grade beams will be 30" deep and I don't want to form them up. The soil holds up vertically pretty well but the 30" trenches may collapse while placing rebar.

Is there any kind of sticky stuff to spray on the trench walls after digging to keep them for caving in while working in them?

 

[DRC1]

OSHA requires the slope laid back if the trench is deeper than 4 feet. If you are only 30 inches deep, the sand is medim dense to dense and you are above the water table, you should be okay. If the material does ravel, the slope can be laid back a little. Obviously climbing in an out will caue some local raveling, so limit areas of entrance and egress. Also try to have the excavation open for the shoest period possible and avoid adverse weather.