Soil Nail Head
Soil Nail Head
(OP)
Hi,
This is more of a construction question on the installation of the soil nail.
Many references call out for the shotcreting of the soil nail wall to be carried out in 2 stages. The first stage is shotcrete until the base plate. Then snug tight the nail bolt and second stage is another concrete layer to cover the soil nail head.
Question is can the shotcreting be done in one and final stage which means shotcrete and cover the soil nail head in one go for a 7 inches (175mm thk) shotcrete wall?
Thanks for any reply
This is more of a construction question on the installation of the soil nail.
Many references call out for the shotcreting of the soil nail wall to be carried out in 2 stages. The first stage is shotcrete until the base plate. Then snug tight the nail bolt and second stage is another concrete layer to cover the soil nail head.
Question is can the shotcreting be done in one and final stage which means shotcrete and cover the soil nail head in one go for a 7 inches (175mm thk) shotcrete wall?
Thanks for any reply





RE: Soil Nail Head
RE: Soil Nail Head
Install the nails
Shoot the facing with reinforcement
Place the bearing plate and nut
Then shoot a hump over the bearing plate and nut.
The purpose of the hump is to provide corrosion protection only. The question is will the owner be willing to accept a wall with humps on the facing. This detail has been used on many projects such as power plants where the owner is not too overly concerned with the aesthetics of the final product. One item of caution when building the wall is that you need to be careful that the shotcrete will stay on the wall when you shoot the humps. To this end it is typical to shoot the cover for the nail heads at the end of the day or the next day. If you are using accelerator in the shotcrete mix this will help with the installation.
RE: Soil Nail Head
No doubt it is easy to shotcrete around the soil nail without the base plate, the soil nail head has to be masked to protected from the shotcrete concrete so that the base plate and the nut can be installed easily later.
In order to hide the soil nail, I intend to have a single THICK layer about 8 inches.
So I wonder is there other major problem if I will to adopt one single stage shotcrete process instead of 2?
Another question is that the design and placement of the rebars. Where is the saggging and hogging moment? At midspan is the sagging moment occurs away from the soil side and hogging moment closest to the soil?
RE: Soil Nail Head
RE: Soil Nail Head
If you space the plate say 80mm off the soil face (perhaps using two nuts) and secure the mesh reinforcement behind the plates, you should be able to shotcrete the face and embed the soil nail head and plate in the concrete. 175mm is a bit thin and won't leave you much cover to play with, and you will have to size the head to keep the shear stress in the concrete within acceptable limits, but it is certainly do-able.
RE: Soil Nail Head
RE: Soil Nail Head
RE: Soil Nail Head