Trench Layback

[nres]

When digging a utility trench, a waterline for ex., in hawaii if the trench height is above 4ft, shoring or layback is required.

ex: The trench section requires the final backfill material to the bottom of subgrade to be select granular fill.

The question is: When sloping or benching the trench from the 4ft elevation and above, can you get away with throwing that excavated material back into the trench to fill the sides (where we laidback the trench), or will you actually fill the sloped sides (voids) with the select granular fill?

 

[beton1]

I think it depends on what is going on top, ie. road/sidewalk/landscape. You show topsoil. So unless it is critical (and the spoils ie.excavated dirt are poor material) then it should be OK. Aloha.