Soil nailing questions

[killswitchengage]

Hello friends
What to do if the compressive strength of the grout used for soil nailing does not meet the minimum required value?
Also what to do in term of grout formulation that's gonna be used for nailing in permeable terrain?

Thank you

 

[PEinc]

Were any nails tested that had the lower strength grout? If so, were the nail tests successful?
Tieback anchors and nails very often are installed in permeable soils. I have never seen nor read about a special formulation needed for the grout.

http://www.PeirceEngineering.com

 

[killswitchengage]

I was referring to compression tests on prismes that gave low ucs for one grout application only. All other results for grout testing were satisfactory.

About the second subject, ive read about possible loss of grout in highly permeable terrain and the necessity to use geotextil socks wrapped around the nails

 

[PEinc]

I know that tieback anchors have been installed inside geotextile socks to prevent the grout from running into the very porous granular soil but I have never seen it done in about 45 years. It may work but I recommend performing pre-production pullout tests to confirm the "bond" of the grouted sock to the soil.
It may be worth trying considering soil screw (helical) nails that need no grout.

http://www.PeirceEngineering.com

 

[killswitchengage]

Thank you so muc mr peinc

 

[killswitchengage]

Hello

I don want to spam another thread, so what are the solutions when the shotcrete has lower compressive strength than the required value in the contract?

 

[PEinc]

Check the design for the lower strength. Is it a temporary or permanent shotcrete facing? Durability may be the controlling issue with lower strength shotcrete.

http://www.PeirceEngineering.com

 

[killswitchengage]

It's a permanant solution. Thank you

 

[Waxwing]

I agree with PEinc: I also don't recall a "special formulation needed for the grout."

Check with the design engineer: the strength of the grout and the bond between the grout and the metal nail are likely not controlling.

It is so reassuring to have test/proof nails--one of the rare instances in civil engineering where this happens.