Nailing through CFA Wall

[MSEMan]

I'm looking at an application for soil nailing in Long Island. The fills are alternatively decribed as "fill" and glacial till. Typical crap decriptions. However, where the the fills are present they are described as med dense sands and gravels, so to retain I'd like to propose soil nailing. However when we cut them they'll collapse. So I'm thinking of installing a row of soldier CFA piles along the cut line (installed hit and miss to let the concrete go off) using a very weak mix to allow us to drill through the CFA wall and install the nail.

Am I missing somethng?

 

[jdonville]

MSEMan,

Why not just construct a permanent tieback wall using H-Piles placed in CFA piles? We're using this technique on a 19-foot excavation to be constructed later this summer. The trick is to fabricate the H-Piles prior to construction so that you can install the tiebacks and preserve the shear and moment capacity of the section.

Jeff

 

[PEinc]

Soil naiing is most appropriate where there is some soil cohesion, where the temporary excavation will stand vertically, and where you can drill open holes for the nails. You do not have these conditions. Soil nailing can be done without these conditions but it becomes more difficult and more expensive. Your idea of using the soil nail wall and CFA piles is even more expensive. You seem to be going out of your way to make an inappropriate application work.

How high will your wall need to be? I agree with jdonville that a soldier beam wall, tiedback if needed, may be a better way to go.